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Sorokowski P, Kowal M. Relationship between the 2D:4D and prenatal testosterone, adult level testosterone, and testosterone change: Meta-analysis of 54 studies. AMERICAN JOURNAL OF BIOLOGICAL ANTHROPOLOGY 2024; 183:20-38. [PMID: 37795916 DOI: 10.1002/ajpa.24852] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2022] [Revised: 08/29/2023] [Accepted: 09/12/2023] [Indexed: 10/06/2023]
Abstract
The ratio between the hands' second to the fourth finger (2D:4D) is commonly hypothesized to result from prenatal testosterone. The 2D:4D has also been hypothesized to relate to adult-level testosterone and, more recently, to the testosterone response to a challenging situation. In the present work, we tested these core assumptions. Drawing from, in total, 54 studies and 8077 participants, we investigated whether the 2D:4D is related to adult level testosterone (44 studies), testosterone change (6 studies), and prenatal testosterone (10 studies). We found no evidence of the relationship between the above testosterone types and digit ratios. Furthermore, there was no relationship between testosterone and the right and left 2D:4D, male and female 2D:4D, and the 2D:4D and testosterone measurement (i.e., measured in blood or saliva). However, we found some evidence that prenatal testosterone measured in amniotic fluid (but not cord blood) might be related to the digit ratios-further studies are necessary to validate this observation. In summary, considering the current state of knowledge, any conclusions drawn from the assumption of the digit ratios as the proxy for testosterone (prenatal, adult level, or testosterone change under a challenging situation) warrant great caution.
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Affiliation(s)
| | - Marta Kowal
- IDN Being Human Lab, University of Wrocław, Wrocław, Poland
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2
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Gurok MG, Yıldız S, Bakış Aksoy D, Kılıçaslan AK, Tabara MF, Yılmaz T, Kaya K, Danacı Keleş D, Karakaş Ş, Şimşek D, Atmaca M. Second and fourth (2D:4D) digit ratio in heroin and cannabis addicted patients. J Ethn Subst Abuse 2023:1-14. [PMID: 38043030 DOI: 10.1080/15332640.2023.2278475] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2023]
Abstract
The etiology of addiction has not yet been fully elucidated. The ratio between the length of the second and fourth fingers (2D:4D ratio) has been linked with prenatal androgen concentrations, but also with addictive behvaiors. Aim: The present study aimed to evaluate the differences of 2D:4D ratio of individuals with cannabis and heroin addiction by examining them together with the control group. A total of sixty two male patients (33 opiate use disorder and 29 cannabis use disorder) with substance use disorder and the twenty-nine healthy controls were included in the present investigation. We obtained the lengths of 2D and 4D of the subjects by using sensitive calipers and calculated the 2D:4D. Heroin-addicted patients had lower 2D:4D ratio in in the right hand (significant difference between control group) (p < 0.001), there was no significant difference found between heroin-cannabis (p = 0.242) and control-cannabis 2D:4D ratios (p < 0.06). In the left hand, it was significant between the heroin-control groups (p < 0.037) and the cannabis-control groups (p < 0.023), while it was not significant between the heroin-cannabis groups (p = 1). In conclusion, we suggest that heroin-and cannabis addicted patients seem to have a lower ratio of 2D:4D compared to healthy control subjects. Our findings can be considered promising as to whether prenatal hormonal factors are important in the etiopathogenesis of addiction.
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Affiliation(s)
- Mehmet Gurkan Gurok
- Faculty of Medicine, Department of Psychiatry, Fırat University, Elazig, Turkey
| | - Sevler Yıldız
- Department of Psychiatry, Fethi Sekin City Hospital, Elazig, Turkey
| | | | | | | | - Tuba Yılmaz
- Department of Psychiatry, Fethi Sekin City Hospital, Elazig, Turkey
| | - Kamer Kaya
- Elazığ Mental Health Hospital, Elazig, Turkey
| | | | - Şahin Karakaş
- Faculty of Medicine, Department of Psychiatry, Fırat University, Elazig, Turkey
- Department of Psychiatry, Sorgun State Hospital, Yozgat, Turkey
| | | | - Murad Atmaca
- Faculty of Medicine, Department of Psychiatry, Fırat University, Elazig, Turkey
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3
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Lenz B, Gerhardt S, Boroumand-Jazi R, Eichler A, Buchholz VN, Fasching PA, Kornhuber J, Banaschewski T, Flor H, Guldner S, Prignitz M, Nees F. Sex-specific association between prenatal androgenization (second-to-fourth digit length ratio) and frontal brain volumes in adolescents. Eur Arch Psychiatry Clin Neurosci 2023; 273:1243-1254. [PMID: 36449103 PMCID: PMC10449726 DOI: 10.1007/s00406-022-01515-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Accepted: 10/26/2022] [Indexed: 12/03/2022]
Abstract
Prenatal androgenization associates sex-dependently with behavior and mental health in adolescence and adulthood, including risk-taking, emotionality, substance use, and depression. However, still little is known on how it affects underlying neural correlates, like frontal brain control regions. Thus, we tested whether prenatal androgen load is sex-dependently related to frontal cortex volumes in a sex-balanced adolescent sample. In a cross-sectional magnetic resonance imaging study, we examined 61 adolescents (28 males, 33 females; aged 14 or 16 years) and analyzed associations of frontal brain region volumes with the second-to-fourth digit length ratio (2D:4D), an established marker for prenatal androgenization, using voxel-based morphometry in a region-of-interest approach. Lower 2D:4D (indicative of higher prenatal androgen load) correlated significantly with smaller volumes of the right anterior cingulate cortex (r-ACC; β = 0.45) in male adolescents and with larger volumes of the left inferior frontal gyrus orbital part (l-IFGorb; β = - 0.38) in female adolescents. The regression slopes of 2D:4D on the r-ACC also differed significantly between males and females. The study provides novel evidence that prenatal androgenization may influence the development of the frontal brain in a sex- and frontal brain region-specific manner. These effects might contribute to the well-known sex differences in risk-taking, emotionality, substance use, and depression. Future research is needed to elucidate the role of prenatal androgenization within the biopsychosocial model.
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Affiliation(s)
- Bernd Lenz
- Department of Addictive Behavior and Addiction Medicine, Central Institute of Mental Health (CIMH), Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany.
- Department of Psychiatry and Psychotherapy, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany.
| | - Sarah Gerhardt
- Department of Addictive Behavior and Addiction Medicine, Central Institute of Mental Health (CIMH), Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Rafat Boroumand-Jazi
- Department of Addictive Behavior and Addiction Medicine, Central Institute of Mental Health (CIMH), Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Anna Eichler
- Department of Child and Adolescent Mental Health, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Verena Nadine Buchholz
- Department of Psychiatry and Psychotherapy, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Peter A Fasching
- Department of Obstetrics and Gynecology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Johannes Kornhuber
- Department of Psychiatry and Psychotherapy, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Tobias Banaschewski
- Department of Child and Adolescent Psychiatry and Psychotherapy, Central Institute of Mental Health (CIMH), Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Herta Flor
- Institute of Cognitive and Clinical Neuroscience, Central Institute of Mental Health (CIMH), Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Stella Guldner
- Department of Child and Adolescent Psychiatry and Psychotherapy, Central Institute of Mental Health (CIMH), Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
- Institute of Cognitive and Clinical Neuroscience, Central Institute of Mental Health (CIMH), Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Maren Prignitz
- Institute of Cognitive and Clinical Neuroscience, Central Institute of Mental Health (CIMH), Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Frauke Nees
- Department of Child and Adolescent Psychiatry and Psychotherapy, Central Institute of Mental Health (CIMH), Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
- Institute of Cognitive and Clinical Neuroscience, Central Institute of Mental Health (CIMH), Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
- Institute of Medical Psychology and Medical Sociology, University Medical Center Schleswig Holstein, Kiel University, Kiel, Germany
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4
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Çay M, Gürel S. The relationship between mothers' second and fourth finger lengths (2D:4D) and anthropometric measurements (height, weight, head circumference, and 2D:4D) of the newborns. Am J Hum Biol 2021; 34:e23700. [PMID: 34751980 DOI: 10.1002/ajhb.23700] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Revised: 10/21/2021] [Accepted: 10/23/2021] [Indexed: 11/09/2022] Open
Abstract
OBJECTIVES In our study, the relationship between male and female newborns' second finger (2D) and fourth finger (4D) lengths, height, weight, and head circumference measurements and their mothers' 2D and 4D lengths was examined. METHODS One hundred and twenty mothers between the ages of 18 and 40 who recently gave birth and 60 females and 60 males newborns of these mothers participated in the study. Height, weight, and head circumference measurements of newborns were taken after birth. 2D and 4D length measurements of newborns and their mothers were made with a caliper with 0.01 mm precision which had. RESULTS Right 2D:4D ratio (0.95 ± 0.08) of male newborns was found to be lower when compared with the right 2D:4D (1.00 ± 0.17) ratio of female newborns. Left 2D:4D ratio of male newborns (0.96 ± 0.07) was also found to be lower when compared with the left 2D:4D (0.98 ± 0.12) ratio of female newborns. Significant positive correlation was found between right 2D lengths of mothers of male newborns and newborns' weight and head diameter and between mothers' 2D:4D ratio and newborns' head diameter. Significant positive correlation was found between right 2D and 4D lengths of mothers of female newborns and female newborns' height, head circumference and right 2D and 4D lengths of female newborns. Significant positive correlation was found between left 2D lengths of mothers and female newborns' height, weight, and head circumference. CONCLUSIONS We think that the data obtained in our study will provide basic information for obstetricians in determining prenatal measurements and for neonatal physicians after delivery.
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Affiliation(s)
- Mahmut Çay
- Faculty of Medicine, Department of Anatomy, Uşak University, Uşak, Turkey
| | - Selçuk Gürel
- Department of Pediatrics, Uşak Öztan Hospital, Uşak, Turkey
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5
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Pasanen BE, Tomkinson JM, Dufner TJ, Park CW, Fitzgerald JS, Tomkinson GR. The relationship between digit ratio (2D:4D) and muscular fitness: A systematic review and meta-analysis. Am J Hum Biol 2021; 34:e23657. [PMID: 34331730 DOI: 10.1002/ajhb.23657] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 07/18/2021] [Accepted: 07/20/2021] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Digit ratio (2D:4D), a marker of prenatal testosterone exposure, is a weak negative correlate of sports/athletic/fitness performance. While numerous studies have examined the relationship between 2D:4D and physical fitness, there has never been a comprehensive study that has synthesized studies examining relationships between 2D:4D and muscular fitness. OBJECTIVES To systematically review and meta-analyze the relationship between 2D:4D and muscular fitness measured as handgrip strength (HGS). METHODS We systematically searched five electronic databases, reference lists, topical systematic reviews/meta-analyses, and personal libraries in November 2020. Peer-reviewed, cross-sectional studies that reported Pearson's correlation coefficients between objectively measured 2D:4D and HGS were included. We used random-effects meta-analysis to estimate the pooled correlation and the 95% confidence interval (95%CI), and moderator analyses to estimate the influence of sex and age. RESULTS Data from 22 studies, representing 5271 individuals from 11 countries ranging in (mean) age from 10.4 to 58.0 years, were included. Overall, there was a weak negative correlation between 2D:4D and HGS (r = -0.15, 95%CI = -0.20 to -0.09), indicating that individuals with low 2D:4Ds had high HGS. We found substantial heterogeneity between studies (Q = 123.4, p < .0001; I2 = 74%), but neither sex (Q = 0.003, p = .96) nor age (Q = 0.46, p = .50) significantly moderated the pooled correlation. CONCLUSIONS We found a weak negative relationship between 2D:4D and HGS, which showed substantial heterogeneity between studies, but was neither moderated by sex nor age. Our finding probably reflects both the long-term (organizational) and short-term (activational) benefits of testosterone.
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Affiliation(s)
- Brooke E Pasanen
- Department of Education, Health and Behavior Studies, University of North Dakota, Grand Forks, North Dakota, USA
| | - Jordan M Tomkinson
- Department of Education, Health and Behavior Studies, University of North Dakota, Grand Forks, North Dakota, USA
| | - Trevor J Dufner
- Department of Education, Health and Behavior Studies, University of North Dakota, Grand Forks, North Dakota, USA
| | - Chan Woong Park
- Department of Education, Health and Behavior Studies, University of North Dakota, Grand Forks, North Dakota, USA
| | - John S Fitzgerald
- Department of Education, Health and Behavior Studies, University of North Dakota, Grand Forks, North Dakota, USA
| | - Grant R Tomkinson
- Department of Education, Health and Behavior Studies, University of North Dakota, Grand Forks, North Dakota, USA.,Alliance for Research in Exercise, Nutrition and Activity (ARENA), Allied Health and Human Performance, University of South Australia, Adelaide, South Australia, Australia
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6
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Vorsatz M, Sanchez-Pages S, Turiegano E. Masculinity and Lying. Front Psychol 2021; 12:684226. [PMID: 34393911 PMCID: PMC8360853 DOI: 10.3389/fpsyg.2021.684226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Accepted: 06/21/2021] [Indexed: 11/13/2022] Open
Abstract
Dishonesty in communication has important economic implications. The standing literature has shown that lying is less pervasive than predicted by standard economic theory. We explore whether biology can help to explain this behavior. In a sample of men, we study whether masculine traits are related to (dis)honesty in a sender-receiver game. We study three masculine physical traits: the second-to-fourth digit ratio, facial morphometric masculinity and the facial width-to-height ratio. These biomarkers display significant associations with lying and deception in the game. We also explore the extent to which these effects operate through social preferences or through beliefs about the behavior of receivers.
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Affiliation(s)
- Marc Vorsatz
- Department of Economic Analysis, National University of Distance Education (UNED), Madrid, Spain
| | | | - Enrique Turiegano
- Department of Biology, Autonomous University of Madrid, Madrid, Spain
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7
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Second to fourth (2D:4D) digit ratio and their relationships among a mother and child population in Ghana. Sci Rep 2021; 11:13028. [PMID: 34158576 PMCID: PMC8219683 DOI: 10.1038/s41598-021-92358-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Accepted: 06/07/2021] [Indexed: 11/12/2022] Open
Abstract
The study aimed to determine the relationship between digit ratios among a mother–child population in Ghana. This was a cross-sectional study from December 2020 to April 2021 involving 272 mothers, their daughters (n = 132) and their sons (n = 140). The right (2D:4DR) and the left (2D:4DL) digit ratios were measured using computer-assisted analysis. The data were analysed in SPSS (v23) and GraphPad Prism (v8) at an alpha value of 0.05. The mean ± SD age of the mothers was 23.9 ± 3.67 years while the median (IQR) age of daughters was 116(54–240) days and sons, 134(54–240) days. The mean ± SD 2D:4DR were 0.94 ± 0.04, 0.91 ± 0.04 and 0.90 ± 0.04 respectively for mothers, daughters and sons. The mean ± SD 2D:4DL was 0.93 ± 0.04, for mothers, 0.92 ± 0.05 for daughters and 0.92 ± 0.05 for sons. The daughters and sons showed leftward asymmetry while the mothers showed rightward asymmetry in digit ratios. The 2D:4DR of sons was significantly lower than daughters (P = 0.031). There were negative correlations between the 2D:4DL and age of daughters (r = −0.182, P = 0.043) and sons (r = −0.221, P = 0.012). The 2D:4DR of mothers was positively correlated with that of daughters (r = 0.332, P = 0.000) and that of sons (r = 0.233, P = 0.008). There are significant relationships between digit ratios in a mother–child population.
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8
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Investigating the reliability and sex differences of digit lengths, ratios, and hand measures in infants. Sci Rep 2021; 11:10998. [PMID: 34040007 PMCID: PMC8155043 DOI: 10.1038/s41598-021-89590-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Accepted: 04/23/2021] [Indexed: 11/08/2022] Open
Abstract
Hands and digits tend to be sexually dimorphic and may reflect prenatal androgen exposure. In the past years, the literature introduced several hand and digit measures, but there is a lack of studies in prepubertal cohorts. The available literature reports more heterogeneous findings in prepubertal compared to postpubertal cohorts. The comparability of the available studies is further limited by the study design and different measurement techniques. The present study compared the reliability and sex differences of available hand and digit measures, namely digit lengths of 2D, 3D, 4D, 5D, digit ratios 2D:4D, 2D:5D, 3D:4D, 3D:5D, 4D:5D, relative digit lengths rel2, rel3, rel4, rel5, directional asymmetry of right and left 2D:4D (Dr-l), hand width, length, and index of 399 male and 364 female 6-month-old German infants within one study using only indirect and computer-assisted measurements. The inter-examiner reliability was excellent while the test-retest reliability of hand scans was only moderate to high. Boys exhibited longer digits as well as wider and longer hands than girls, but smaller digit ratios, with ratios comprising the fifth digit revealing the largest effect sizes. Other hand and digit ratios revealed sex differences to some extent. The findings promote the assumption of sexual dimorphic hand and digit measures. However, by comparing the results of the available literature, there remains an uncertainty regarding the underlying hypothesis. Specifically in prepubertal cohorts, i.e. before the influence of fluctuating hormones, significant effects should be expected. It seems like other factors than the influence of prenatal androgens contribute to the sexual dimorphism in hand and digit lengths.
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Fusar-Poli L, Rodolico A, Sturiale S, Carotenuto B, Natale A, Arillotta D, Siafis S, Signorelli MS, Aguglia E. Second-to-Fourth Digit Ratio (2D:4D) in Psychiatric Disorders: A Systematic Review of Case-control Studies. CLINICAL PSYCHOPHARMACOLOGY AND NEUROSCIENCE : THE OFFICIAL SCIENTIFIC JOURNAL OF THE KOREAN COLLEGE OF NEUROPSYCHOPHARMACOLOGY 2021; 19:26-45. [PMID: 33508786 PMCID: PMC7851454 DOI: 10.9758/cpn.2021.19.1.26] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 07/24/2020] [Accepted: 07/26/2020] [Indexed: 12/22/2022]
Abstract
The second-to-fourth digit ratio (2D:4D) is an indirect, retrospective, non-invasive measure that correlates negatively with intrauterine exposure to testosterone. The present meta-analysis aimed to evaluate if 2D:4D differs between patients with psychiatric disorders and controls. In September 2019, we searched in Web of Knowledge, PsycINFO, Embase, and CINHAL, and retrieved 619 papers. We finally included 43 case-control studies which compared the 2D:4D ratio of patients with autism spectrum disorder (ASD) (n = 16), schizophrenia (n = 8), gender non-conformity (n = 7), addictions (n = 5), attention deficit-hyperactivity disorder (ADHD) (n = 4), mood disorders (n = 2), and intellectual disability (n = 1) to non-clinical controls. Meta-analyses showed that, overall, psychiatric patients had lower 2D:4D than healthy controls (n = 43, overall sample = 9,484, mean difference = -0.0056, 95% confidence interval from -0.0093 to -0.002, I2 = 74%), with more pronounced differences in the right hand, males, and children. Considering psychiatric disorders individually, significant differences were found in the ASD, ADHD, and addictions groups, in which 2D:4D was significantly lower than healthy controls. Conversely, the right hand of males with schizophrenia showed higher 2D:4D than healthy controls. No other significant differences were detected. Although our results need to be cautiously interpreted and find limited applications in clinical practice, they may suggest that 2D:4D is altered in some psychopathological conditions, underlining the role of prenatal exposure to sex steroids in the etiology of psychiatric disorders.
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Affiliation(s)
- Laura Fusar-Poli
- Department of Clinical and Experimental Medicine, Psychiatry Unit, University of Catania, Catania, Italy
| | - Alessandro Rodolico
- Department of Clinical and Experimental Medicine, Psychiatry Unit, University of Catania, Catania, Italy
| | - Serena Sturiale
- Department of Clinical and Experimental Medicine, Psychiatry Unit, University of Catania, Catania, Italy
| | - Bianca Carotenuto
- Department of Clinical and Experimental Medicine, Psychiatry Unit, University of Catania, Catania, Italy
| | - Antimo Natale
- Department of Clinical and Experimental Medicine, Psychiatry Unit, University of Catania, Catania, Italy
| | - Davide Arillotta
- Department of Clinical and Experimental Medicine, Psychiatry Unit, University of Catania, Catania, Italy
| | - Spyridon Siafis
- Department of Psychiatry and Psychotherapy, School of Medicine, Technical University of Munich, Munich, Germany
| | - Maria Salvina Signorelli
- Department of Clinical and Experimental Medicine, Psychiatry Unit, University of Catania, Catania, Italy
| | - Eugenio Aguglia
- Department of Clinical and Experimental Medicine, Psychiatry Unit, University of Catania, Catania, Italy
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Richards G, Medland SE, Beaton AA. Digit ratio (2D:4D) and handedness: A meta-analysis of the available literature. Laterality 2021; 26:421-484. [PMID: 33517845 DOI: 10.1080/1357650x.2020.1862141] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The Geschwind-Behan-Galaburda and sexual differentiation models predict an association between elevated foetal androgen exposure and left-handedness whereas the callosal hypothesis predicts the opposite. We present a meta-analysis of correlations between handedness and digit ratio (2D:4D), a putative marker of prenatal testosterone. Left-handedness predicted low (male-typical) right-hand digit ratio (R2D:4D), high (female-typical) left-hand digit ratio (L2D:4D), and low R2D:4D-L2D:4D directional asymmetry (D[R-L]). Effect sizes were extremely small and not moderated by sex or method of measuring handedness or 2D:4D. The same general pattern was observed after excluding the very large study (110,329 males, 90,412 females) of Manning and Peters ([2009]. Digit ratio (2D:4D) and hand preference for writing in the BBC Internet Study. Laterality: Asymmetries of Body, Brain and Cognition, 14(5), 528-540. doi:10.1080/13576500802637872); however, no significant effects for R2D:4D were observed once these samples were removed. The results do not confirm any theory linking prenatal androgens with handedness, so we speculate they instead reflect the mechanical action of writing causing subtle changes in the musculature and/or fat pads of the fingers. Gripping a pen/pencil might cause an increase in 2D relative to 4D (and/or decrease in 4D relative to 2D) resulting in higher ratios on the writing-hand; furthermore, this could differ between left- and right-handers due to writing in the left-to-right direction (as in English) having asymmetrical effects depending on which hand is used.
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Affiliation(s)
- Gareth Richards
- School of Psychology, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK.,Autism Research Centre, Department of Psychiatry, University of Cambridge, Cambridge, UK.,Centre for Research on Play in Education, Development & Learning, Faculty of Education, University of Cambridge, Cambridge, UK
| | - Sarah E Medland
- Psychiatric Genetics, QIMR Berghofer Medical Research Institute, Brisbane, Australia.,School of Psychology, University of Queensland, St Lucia, Australia.,School of Psychology and Counselling, Queensland University of Technology, Brisbane, Australia
| | - Alan A Beaton
- Department of Psychology, School of Human & Health Sciences, Swansea University, Swansea, UK.,Department of Psychology, Aberystwyth University, Aberystwyth, UK
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11
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van Leeuwen B, Smeets P, Bovet J, Nave G, Stieglitz J, Whitehouse A. Do sex hormones at birth predict later-life economic preferences? Evidence from a pregnancy birth cohort study. Proc Biol Sci 2020; 287:20201756. [PMID: 33352071 PMCID: PMC7779492 DOI: 10.1098/rspb.2020.1756] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 11/27/2020] [Indexed: 12/12/2022] Open
Abstract
Economic preferences may be shaped by exposure to sex hormones around birth. Prior studies of economic preferences and numerous other phenotypic characteristics use digit ratios (2D : 4D), a purported proxy for prenatal testosterone exposure, whose validity has recently been questioned. We use direct measures of neonatal sex hormones (testosterone and oestrogen), measured from umbilical cord blood (n = 200) to investigate their association with later-life economic preferences (risk preferences, competitiveness, time preferences and social preferences) in an Australian cohort (Raine Study Gen2). We find no significant associations between testosterone at birth and preferences, except for competitiveness, where the effect runs opposite to the expected direction. Point estimates are between 0.05-0.09 percentage points (pp) and 0.003-0.14 s.d. We similarly find no significant associations between 2D : 4D and preferences (n = 533, point estimates 0.003-0.02 pp and 0.001-0.06 s.d.). Our sample size allows detecting effects larger than 0.11 pp or 0.22 s.d. for testosterone at birth, and 0.07 pp or 0.14 s.d. for 2D : 4D (α = 0.05 and power = 0.90). Equivalence tests show that most effects are unlikely to be larger than these bounds. Our results suggest a reinterpretation of prior findings relating 2D : 4D to economic preferences, and highlight the importance of future large-sample studies that permit detection of small effects.
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Affiliation(s)
- Boris van Leeuwen
- Department of Economics, Tilburg University, Tilburg, The Netherlands
| | - Paul Smeets
- Department of Finance, Maastricht University, Maastricht, The Netherlands
| | - Jeanne Bovet
- Department of Psychology, Northumbria University, Newcastle upon Tyne, UK
| | - Gideon Nave
- Department of Marketing, The Wharton School, University of Pennsylvania, Philadelphia, PA, USA
| | - Jonathan Stieglitz
- Institute for Advanced Study in Toulouse, University of Toulouse 1 Capitole, Toulouse, France
| | - Andrew Whitehouse
- Telethon Kids Institute, University of Western Australia, Crawley, Western Australia, Australia
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12
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Kɪlɪç F, Işɪk Ü, Demirdaş A, İnci HE. Investigation of second to fourth finger length ratio (2D:4D) in patients with bipolar disorder. ACTA ACUST UNITED AC 2020; 42:617-620. [PMID: 32555980 PMCID: PMC7678901 DOI: 10.1590/1516-4446-2019-0836] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2019] [Accepted: 02/29/2020] [Indexed: 12/04/2022]
Abstract
Objective: The etiology of bipolar disorder has yet to be fully elucidated, but differences in sex hormones have been suggested to play a role in its pathogenesis. An easily assessed marker of prenatal androgen exposure is the second-to-fourth-digit ratio (2D:4D) of the hand. In this study, we aimed to compare the 2D:4D ratio of patients with bipolar disorder to that of healthy controls. Methods: Seventy patients with bipolar disorder and 70 healthy controls, matched for age and sex, were included in the study. Finger lengths were measured from the palmar digital crease to the tip using a digital vernier caliper. Results: Patients with bipolar disorder had considerably higher right-hand 2D:4D ratios compared to controls. Both the right and left 2D:4D ratios of male patients were significantly greater than those of males in the control group. Female patients showed no differences in right or left 2D:4D ratio compared to healthy controls. Conclusion: These findings suggest that a high 2D:4D digit ratio of right hand is associated with the presence of bipolar disorder in males. Further large-scale, prospective studies are needed to explain the validity of this marker and its relationship with bipolar disorder.
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Affiliation(s)
- Faruk Kɪlɪç
- Department of Psychiatry, Süleyman Demirel University Medicine Faculty, Isparta, Turkey
| | - Ümit Işɪk
- Department of Child and Adolescent Psychiatry, Süleyman Demirel University Medicine Faculty, Isparta, Turkey
| | - Arif Demirdaş
- Department of Psychiatry, Süleyman Demirel University Medicine Faculty, Isparta, Turkey
| | - Hüseyin E İnci
- Department of Psychiatry, Süleyman Demirel University Medicine Faculty, Isparta, Turkey
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13
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Richards G, Browne WV, Aydin E, Constantinescu M, Nave G, Kim MS, Watson SJ. Digit ratio (2D:4D) and congenital adrenal hyperplasia (CAH): Systematic literature review and meta-analysis. Horm Behav 2020; 126:104867. [PMID: 32998030 DOI: 10.1016/j.yhbeh.2020.104867] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 09/18/2020] [Accepted: 09/19/2020] [Indexed: 01/15/2023]
Abstract
The ratio of length between the second and fourth fingers (2D:4D) is commonly used as an indicator of prenatal sex hormone exposure. Several approaches have been used to try to validate the measure, including examining 2D:4D in people with congenital adrenal hyperplasia (CAH), a suite of conditions characterised by elevated adrenal androgen production secondary to defective steroidogenesis. We present a systematic review and meta-analysis that examines the relationship between these two variables. Twelve articles relating to nine CAH cohorts were identified, and 2D:4D comparisons have been made between cases and controls in eight of these cohorts. Altogether, at least one 2D:4D variable has been compared between n = 251 females with CAH and n = 358 unaffected females, and between n = 108 males with CAH and n = 204 unaffected males. A previous meta-analysis (Hönekopp and Watson, 2010) reported lower right hand (R2D:4D) and left hand (L2D:4D) digit ratios in patients with CAH relative to sex-matched controls. Our meta-analysis showed the same pattern, with medium effect sizes for R2D:4D and small effect sizes for L2D:4D. Differences of small magnitude were also observed for M2D:4D, and no significant effects were observed for D[R-L]. Notably, the only effects that remained statistically significant when stratified by sex were R2D:4D in males and L2D:4D in females, and the average effect size had reduced by 46.70% since the meta-analysis of Hönekopp and Watson (2010). We also found that individual comparisons in this literature were considerably underpowered, and that patterns of sexual dimorphism in 2D:4D were similar in CAH samples as in typically developing populations. Findings are discussed in relation to the prenatal androgen hypothesis as well as alternative explanations.
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Affiliation(s)
- Gareth Richards
- School of Psychology, Faculty of Medical Sciences, Newcastle University, UK; Autism Research Centre, Department of Psychiatry, University of Cambridge, UK.
| | | | - Ezra Aydin
- Autism Research Centre, Department of Psychiatry, University of Cambridge, UK
| | - Mihaela Constantinescu
- Gender Development Research Centre, University of Cambridge, UK; School of Psychology, University of East London, UK
| | - Gideon Nave
- Marketing Department, The Wharton School, University of Pennsylvania, USA
| | - Mimi S Kim
- Keck School of Medicine, University of Southern California, USA
| | - Steven J Watson
- School of Psychology, Faculty of Medical Sciences, Newcastle University, UK; Department of Psychology of Conflict, Risk and Safety, University of Twente, Netherlands
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14
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Körner LM, Schaper ML, Pause BM, Heil M. Parent-Reports of Sex-Typed Play Preference in Preschool Children: Relationships to 2D:4D Digit Ratio and Older Siblings' Sex. ARCHIVES OF SEXUAL BEHAVIOR 2020; 49:2715-2724. [PMID: 32222854 PMCID: PMC7497428 DOI: 10.1007/s10508-020-01662-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Revised: 02/11/2020] [Accepted: 02/13/2020] [Indexed: 05/06/2023]
Abstract
Sex-typed play behavior shows large sex differences and seems to be affected by prenatal sex hormones. For example, a smaller, more male-typical ratio between the second and fourth digit length (2D:4D), a proposed marker for prenatal testosterone exposure, has been shown to be related to sex-typed play preference in childhood. Nevertheless, it is still being debated whether 2D:4D displays a stable sex difference throughout childhood, as there are few longitudinal studies. In the present study, children's 2D:4D was measured on both hands on four occasions from early infancy to early childhood (T1: 5 months, T2: 9 months, T3: 20 months, and T4: 40 months) providing the rare possibility to test the temporal stability of the sex difference. Parents completed the Preschool Activities Inventory at T4 and reported on the number of older brothers and sisters as a measure for socialization influences. Parents described boys as playing more masculine and less feminine than girls. Boys had smaller 2D:4D than girls at all measurements (T1-T4) and on both hands (right/left). Nevertheless, 2D:4D increased significantly from T3 to T4 in both sexes. Girls, but not boys, who were described as playing more masculine and less feminine had more masculine 2D:4D ratios at T1-T4 on both hands (except for right 2D:4D at T2 and T3) and had more older brothers and fewer older sisters. These data underline the stability of the sex difference in 2D:4D and show the importance of both biological and social influences on sex-typed play behavior.
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Affiliation(s)
- Lisa M Körner
- Department of Experimental Psychology, Institute of Experimental Psychology, Heinrich Heine University Düsseldorf, Universitätsstraße 1, 40225, Düsseldorf, Germany.
| | - Marie Luisa Schaper
- Department of Experimental Psychology, Institute of Experimental Psychology, Heinrich Heine University Düsseldorf, Universitätsstraße 1, 40225, Düsseldorf, Germany
| | - Bettina M Pause
- Department of Experimental Psychology, Institute of Experimental Psychology, Heinrich Heine University Düsseldorf, Universitätsstraße 1, 40225, Düsseldorf, Germany
| | - Martin Heil
- Department of Experimental Psychology, Institute of Experimental Psychology, Heinrich Heine University Düsseldorf, Universitätsstraße 1, 40225, Düsseldorf, Germany
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15
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Lenz B, Mühle C, Kornhuber J. Lower digit ratio (2D:4D) in alcohol dependence: Confirmation and exploratory analysis in a population-based study of young men. Addict Biol 2020; 25:e12815. [PMID: 31418510 DOI: 10.1111/adb.12815] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2019] [Revised: 07/02/2019] [Accepted: 07/04/2019] [Indexed: 12/16/2022]
Abstract
Moderately sized, case-control studies have related alcohol dependence in middle-aged in-patients to lower second-to-fourth finger length ratio (2D:4D), a proxy for prenatal hyperandrogenization. As primary aim, we here intended to confirm that lower 2D:4D is also associated with Diagnostic and Statistical Manual of Mental Disorders (DSM)-IV/-5 alcohol dependence and alcohol use disorder in a large population-based cohort of young males. Exploratory aims included underlying mechanisms. We analyzed self-reported data on 2D:4D, DSM-IV/-5 criteria, anticipated subjective responses to alcohol, and willingness to purchase alcoholic drinks from 4989 Swiss men of the Cohort Study on Substance Use Risk Factors (C-SURF). The mean of right-hand 2D:4D and left-hand 2D:4D was lower in men with DSM-IV alcohol dependence than in those without (0.975 vs 0.981, P = .035) and lower in men with moderate to severe (0.974) than in those with mild (0.982, P = .001) or no (0.981, P = .003) DSM-5 alcohol use disorder. Moreover, mean 2D:4D was lower in those reporting recent use of health services due to substance use problems (0.968 vs 0.981, P = .046). Lower mean 2D:4D correlated with a stronger anticipation to feel high following alcohol consumption (total cohort: ρ = -0.033, P = .026) and with a willingness to purchase more higher-priced alcoholic drinks (DSM-IV alcohol dependence subgroup: ρmin = -0.162, P = .002). This is the first population-based study on young males to demonstrate lower 2D:4D in DSM-IV alcohol dependence, DSM-5 alcohol use disorder, and the related use of health care services. We also provide novel insight into cognitive-behavioral mechanisms. These results should help to establish more effective preventive and therapeutic strategies targeting 2D:4D and prenatal androgen exposure.
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Affiliation(s)
- Bernd Lenz
- Department of Psychiatry and Psychotherapy Friedrich‐Alexander University Erlangen‐Nürnberg (FAU) Erlangen Germany
| | - Christiane Mühle
- Department of Psychiatry and Psychotherapy Friedrich‐Alexander University Erlangen‐Nürnberg (FAU) Erlangen Germany
| | - Johannes Kornhuber
- Department of Psychiatry and Psychotherapy Friedrich‐Alexander University Erlangen‐Nürnberg (FAU) Erlangen Germany
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16
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Lombardo MP, Otieno S. The associations between digit ratio, aerobic fitness, physical skills, and overall physical fitness of elite youth distance runners. Am J Hum Biol 2020; 33:e23448. [PMID: 32501636 DOI: 10.1002/ajhb.23448] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Revised: 04/23/2020] [Accepted: 05/13/2020] [Indexed: 11/11/2022] Open
Abstract
OBJECTIVE Lower digit ratios between the lengths of fingers 2 (2D) and 4 (4D) (2D:4D) are associated with superior distance running and athletic performance. We examined relationships between 2D:4D, aerobic fitness, physical skills, and overall physical fitness of elite adolescent boy and girl distance runners. METHODS Subjects were top five finishers for their sex and age in 10 or more races of 10 km or longer in Michigan in 1981. We calculated 2D:4D of 15 girls and 11 boys from radiographs. Subject peak O2 consumption (VO2Peak ), ventilatory threshold (VT), and point of equivalent change (PEC) were collected during intermittent treadmill protocol tests. Performances on physical skills tests (flex-arm hang, broad jump, vertical jump, figure-8-run, sit ups, and sit-and-reach test) were collected in the laboratory. We examined the interrelationships between 2D:4D, subject sex, aerobic fitness, physical skills test performance, and overall physical fitness, a composite of aerobic and physical skills performance with correlation, linear regression, t tests, and principle component analyses. RESULTS Girls had significantly larger right hand (R) 2D:4D than boys. Boys had greater VO2Peak by mass than girls. Boys with lower R2D:4D had significantly greater VO2Peak and PEC. Girls with lower R2D:4D had significantly greater VT. Factors associated with aerobic fitness explained most of the variation in composite physical fitness scores. Composite aerobic fitness, physical skills, and overall physical fitness scores of boys were negatively correlated with R2D:4D. CONCLUSIONS These data suggest that R2D:4D may help predict distance running performance in girls and boys and overall physical fitness in boys and provide additional insights into the innate factors influencing youth physical fitness.
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Affiliation(s)
- Michael P Lombardo
- Biology Department, Grand Valley State University, Allendale, Michigan, USA
| | - Sango Otieno
- Statistics Department, Grand Valley State University, Allendale, Michigan, USA
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17
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Sadr M, Khorashad BS, Talaei A, Fazeli N, Hönekopp J. 2D:4D Suggests a Role of Prenatal Testosterone in Gender Dysphoria. ARCHIVES OF SEXUAL BEHAVIOR 2020; 49:421-432. [PMID: 31975034 PMCID: PMC7031197 DOI: 10.1007/s10508-020-01630-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Revised: 01/03/2020] [Accepted: 01/06/2020] [Indexed: 06/10/2023]
Abstract
Gender dysphoria (GD) reflects distress caused by incongruence between one's experienced gender identity and one's natal (assigned) gender. Previous studies suggest that high levels of prenatal testosterone (T) in natal females and low levels in natal males might contribute to GD. Here, we investigated if the 2D:4D digit ratio, a biomarker of prenatal T effects, is related to GD. We first report results from a large Iranian sample, comparing 2D:4D in 104 transwomen and 89 transmen against controls of the same natal sex. We found significantly lower (less masculine) 2D:4D in transwomen compared to control men. We then conducted random-effects meta-analyses of relevant studies including our own (k = 6, N = 925 for transwomen and k = 6, N = 757 for transmen). In line with the hypothesized prenatal T effects, transwomen showed significantly feminized 2D:4D (d ≈ 0.24). Conversely, transmen showed masculinized 2D:4D (d ≈ - 0.28); however, large unaccounted heterogeneity across studies emerged, which makes this effect less meaningful. These findings support the idea that high levels of prenatal T in natal females and low levels in natal males play a part in the etiology of GD. As we discuss, this adds to the evidence demonstrating the convergent validity of 2D:4D as a marker of prenatal T effects.
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Affiliation(s)
- Mostafa Sadr
- Transgender Studies Centre, Psychiatry and Behavioral Sciences Research Centre, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Behzad S Khorashad
- Transgender Studies Centre, Psychiatry and Behavioral Sciences Research Centre, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Ali Talaei
- Transgender Studies Centre, Psychiatry and Behavioral Sciences Research Centre, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Nasrin Fazeli
- Transgender Studies Centre, Psychiatry and Behavioral Sciences Research Centre, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Johannes Hönekopp
- Department of Psychology, Northumbria University, Newcastle upon Tyne, NE1 8ST, UK.
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18
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Ertuğrul B, Özener B. Relationship between parental consanguinity and digit ratios (2D:4D) among Turkish newborns in Sivas. Am J Hum Biol 2019; 32:e23369. [PMID: 31801181 DOI: 10.1002/ajhb.23369] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Revised: 11/13/2019] [Accepted: 11/17/2019] [Indexed: 11/11/2022] Open
Abstract
OBJECTIVES The aim of this study was to investigate the effects of parental consanguinity on the 2D:4D digit ratio of newborn infants, whose parents were the first cousins. METHODS The study included healthy and full-term newborn infants, delivered in a hospital, at the gestational ages from 37 to 41 weeks. A total of 225 newborns and their parents were included in the study. Of these 225 newborns; 100 were inbred and 125 were outbred infants. We used a Vernier caliper to measure the length of the second and fourth digits of the newborns (accuracy: 0.01 mm). RESULTS Controlling for education and number of pregnancies, male newborns had lower digit ratios than female newborns, for both left and right hands. There were, moreover, differences between inbred and outbred samples. We determined that inbreeding was related to a reduction in the digit ratios regardless of the side of the hand and the sex of the infant, showing a consistent tendency to appear more masculine. Interaction between marriage type*sex was highly significant. CONCLUSIONS Parental consanguinity appears to cause fetal masculinization of digit ratios by increasing fetal stress among Turkish newborns.
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Affiliation(s)
- Berna Ertuğrul
- Faculty of Literature, Department of Anthropology, Sivas Cumhuriyet University, Sivas, Turkey
| | - Barış Özener
- Faculty of Literature, Department of Anthropology, İstanbul University, İstanbul, Turkey
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19
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Misiak M, Butovskaya M, Oleszkiewicz A, Sorokowski P. Digit ratio and hand grip strength are associated with male competition outcomes: A study among traditional populations of the Yali and Hadza. Am J Hum Biol 2019; 32:e23321. [PMID: 31512345 DOI: 10.1002/ajhb.23321] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2019] [Revised: 08/17/2019] [Accepted: 08/28/2019] [Indexed: 01/03/2023] Open
Abstract
OBJECTIVES Indirect measures of physiological features, such as digit ratio and hand grip strength (HGS), are associated with the outcome of male competition activities. However, most of the studies were conducted in developed and industrialized societies. We tested the hypothesis that both digit ratio and HGS are associated with performance in male-specific activities in two traditional preindustrial societies: Yali and Hadza. METHODS To measure masculine behavioral traits, we determined warriorship status (Yali; n = 49) and assessed hunting skills (Yali n = 47 and Hadza n = 49). We also assessed the digit ratio and HGS of each male. We conducted our analyses using the Bayesian approach. RESULTS Bayesian regression models indicated that greater hand grip strength is associated with better hunting outcomes among Hadza males. We did not find a similar link for the Yali. We found anecdotal evidence for the link between left hand digit ratio and the number of birds hunted by Hadza. We found no evidence for the link between digit ratio and performance in male-male competition. CONCLUSIONS Our results suggest that male-male competition outcomes are determined by upper body strength, but only in the Hadza population. We also found limited support for the hypothesis that digit ratio is associated with hunting success among the Hadza. We found no support for the hypothesis concerning the digit ratio or HGS among the Yali. Our research provides partial support for the evolutionary hypotheses based on studies conducted in industrialized populations.
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Affiliation(s)
- Michał Misiak
- Faculty of Historical and Pedagogical Sciences, Institute of Psychology, University of Wroclaw, Wroclaw, Poland
| | - Marina Butovskaya
- Institute of Ethnology and Anthropology, Russian Academy of Sciences, Moscow, Russia
| | - Anna Oleszkiewicz
- Faculty of Historical and Pedagogical Sciences, Institute of Psychology, University of Wroclaw, Wroclaw, Poland.,Department of Otorhinolaryngology, Smell and Taste Clinic, Dresden, Germany
| | - Piotr Sorokowski
- Faculty of Historical and Pedagogical Sciences, Institute of Psychology, University of Wroclaw, Wroclaw, Poland
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20
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Paukner A. Digit ratio (2D:4D) and its behavioral correlates in infant rhesus macaques (Macaca mulatta). Dev Psychobiol 2019; 62:992-998. [PMID: 31512755 DOI: 10.1002/dev.21917] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Revised: 08/16/2019] [Accepted: 08/17/2019] [Indexed: 11/11/2022]
Abstract
2D:4D ratios are typically lower in adult human males than females and are linked to numerous sex-differentiated behaviors. 2D:4D ratios are considered an indicator of prenatal androgen exposure; if so, children's 2D:4D ratios would arguably be even better indicators of prenatal androgen exposure since children have experienced fewer postnatal influences than adults. However, sex differences in 2D:4D ratios as well as associations between 2D:4D ratios and sex-typed behaviors in children have been inconsistent. Several studies also report sex differences and behavioral correlates of 2D:4D ratios in adult non-human primates, but little is known about 2D:4D ratios in infant non-human primates. This study examined sex differences in 2D:4D ratios over the first month of life, and associations with behavioral outcomes at 12-24 weeks of age, in N = 304 infant rhesus macaques. An increase in 2D:4D ratios over the first month of life was found, as well as associations with aggression and play behaviors, but no sex differences in 2D:4D ratios were observed. These results highlight the need for future developmental studies of 2D:4D ratios in order to determine not only their stability and predictive value, but also to discern the mechanism connecting prenatal androgen exposure, 2D:4D ratios, and behavioral outcomes.
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Affiliation(s)
- Annika Paukner
- Psychology Department, Nottingham Trent University, Nottingham, UK
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21
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Nadler A, Camerer CF, Zava DT, Ortiz TL, Watson NV, Carré JM, Nave G. Does testosterone impair men's cognitive empathy? Evidence from two large-scale randomized controlled trials. Proc Biol Sci 2019; 286:20191062. [PMID: 31480979 DOI: 10.1098/rspb.2019.1062] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The capacity to infer others' mental states (known as 'mind reading' and 'cognitive empathy') is essential for social interactions across species, and its impairment characterizes psychopathological conditions such as autism spectrum disorder and schizophrenia. Previous studies reported that testosterone administration impaired cognitive empathy in healthy humans, and that a putative biomarker of prenatal testosterone exposure (finger digit ratios) moderated the effect. However, empirical support for the relationship has relied on small sample studies with mixed evidence. We investigate the reliability and generalizability of the relationship in two large-scale double-blind placebo-controlled experiments in young men (n = 243 and n = 400), using two different testosterone administration protocols. We find no evidence that cognitive empathy is impaired by testosterone administration or associated with digit ratios. With an unprecedented combined sample size, these results counter current theories and previous high-profile reports, and demonstrate that previous investigations of this topic have been statistically underpowered.
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Affiliation(s)
| | - Colin F Camerer
- Department of the Humanities and Social Sciences, California Institute of Technology, 1200 E California Boulevard, MC 228-77, Pasadena, CA 91125, USA
| | - David T Zava
- ZRT Laboratory, 8605 SW Creekside Place, Beaverton, OR 97008, USA
| | - Triana L Ortiz
- Department of Psychology, Nipissing University, 100 College Drive, North Bay, Ontario, Canada P1B 8L7
| | - Neil V Watson
- Department of Psychology, Simon Fraser University, 8888 University Drive, Burnaby, British Columbia, Canada V5A 1S6
| | - Justin M Carré
- Department of Psychology, Nipissing University, 100 College Drive, North Bay, Ontario, Canada P1B 8L7
| | - Gideon Nave
- Marketing Department, The Wharton School of the University of Pennsylvania, 3730 Walnut Street, Philadelphia, PA 19104, USA
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22
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Is digit ratio (2D:4D) associated with the choice for the uniformed versus a civil study course by the Polish youth? ANTHROPOLOGICAL REVIEW 2019. [DOI: 10.2478/anre-2019-0013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The 2nd to 4th digit ratio (2D:4D) is a sexually dimorphic trait determined by the relative balance of prenatal testosterone (T) and oestrogen during the intrauterine development of foetus. Males on average have relatively lower 2D:4D than women in population. Lower 2D:4D is very often linked with greater physical ability, strength, superior sporting performance and many personality traits and behaviours which are seen more among the males. Recently, lower 2D:4D were associated with military and police services among the Polish women. The objectives of this study were to examine whether 2D:4D differed between the students of a study course for future military service and a civil study course and whether sex difference in this ratio is present in both these groups. The cross sectional study included 50 boys and 42 girls enrolled in the uniformed course and other 56 boys and 50 girls of a general course in an upper-secondary School. The lengths of the second (2D) and fourth fingers (4D) of each hand were measured to have the 2D:4D ratio. Height and weight were also recorded. Overall, as well as among the civil course students, males showed significantly lower mean 2D:4D compared to the females. But there was no significant sex difference in digit ratio among the uniformed course students. Besides, the females under uniformed course showed lower 2D:4D than the females in civil course, whereas, the male uniformed students had similar or almost same 2D:4D values with the male civil course students. Increased prenatal testosterone exposure might have a role in determining the choice towards a challenging future occupation and such effect is perhaps more pronounced in women than in males.
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23
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Agha-Alinejad H, Farzad B, Akbari M, Moffit DM, Dakhili A. Digit ratios and motor and health-related fitness in pre-adolescent females. Ann Hum Biol 2019; 46:225-230. [PMID: 31106581 DOI: 10.1080/03014460.2019.1620332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Background: Assessing different aspects of physical fitness in children whose abilities are undeveloped and their associations with second-to-fourth digit ratio (2D:4D) may better determine the potential athleticism of an individual.Aim: The purpose of the study was to examine relationships between the digit ratios and selected motor and health-related fitness parameters in a large sample of pre-adolescent females.Subjects and methods: Participants included 8-12 year old Iranian and Afghan girls. The length of the left and right second and fourth digits was measured by scanning and computer-assisted image analysis. Motor- and health-related fitness tests were evaluated.Results: No significant correlations were noted between right 2D:4D ratio and physical fitness components. Left 2D:4D and physical fitness components were not correlated, with the exception of handgrip strength (r = -0.193). However, right and left second digit lengths were negatively correlated with predicted VO2max (p ≤ 0.01). In addition, right-left 2D:4D was significantly negatively correlated with flexibility, and significantly positively correlated with height and body fat percentage.Conclusion: In contrast to previous investigations, it seems that left 2D:4D is a predictor of strength, but not aerobic exercise. It is suggested there may be a potential relationship between prenatal androgen exposure and high flexibility, low body fat percentage and the generation of muscular strength in pre-adolescent females.
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Affiliation(s)
- Hamid Agha-Alinejad
- Department of Physical Education and Sports Science, Faculty of Humanities, Tarbiat Modares University, Tehran, Iran
| | - Babak Farzad
- Neuroscience Research Center, Iran University of Medical Sciences, Tehran, Iran.,Department of Physical Education & Sports Science, Azad University, Tehran North Branch, Tehran, Iran
| | - Mina Akbari
- Department of Exercise Physiology, Faculty of Physical Education & Sports Science, Azad University, Tehran Central Branch, Tehran, Iran
| | - Dani M Moffit
- Department of Sport Science and Physical Education, Idaho State University, Pocatello, ID, USA
| | - Amirbahador Dakhili
- Department of Physical Education and Sports Science, Faculty of Humanities, Tarbiat Modares University, Tehran, Iran
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24
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Nafakhi H, Al-Mosawi AA, Mudhafar MM, Al-Nafakh HA, Alsaady R. Digit ratio and hair color relationships with coronary atherosclerotic markers. Asian Cardiovasc Thorac Ann 2019; 27:362-368. [PMID: 31018656 DOI: 10.1177/0218492319847379] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Objective We aimed to investigate the association between body phenotype markers and coronary atherosclerosis markers. Methods Eighty-nine patients (mean age 57 ± 9 years, 50.5% male) who were assessed for coronary artery disease by 64-slice multidetector computed tomography angiography were enrolled in the study. Results A significant positive association was observed between coronary artery calcification and the second to fourth digit ratio ( r = 0.2, p = 0.00); more notably in males compared to females ( p = 0.03 vs. p = 0.08). There was a significant association between coronary artery calcification and pure white hair ( p = 0.00). There was no significant association between pericardial fat volume and second to fourth digit ratio ( p = 0.8). Pericardial fat volume was significantly associated with pure white hair ( p = 0.02). A significant association was observed between coronary plaque and a higher second to fourth digit ratio ( p = 0.01) and this was more notable in males ( p = 0.04). A significant association was observed between pure white hair and coronary plaque ( p = 0.00). After adjustment for conventional cardiac risk factors, the association of coronary artery calcification and coronary plaque with the second to fourth digit ratio did not persist, whereas the association of pericardial fat volume and coronary artery calcification with pure white hair remained significant ( p = 0.01 and p = 0.00, respectively). Conclusion These results suggest a possible predictive value of hair color, rather than digit ratio, in assessing increased risk of coronary atherosclerosis and cardiac fat deposition.
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Affiliation(s)
- Hussein Nafakhi
- 1 Internal Medicine Department, Medicine College, University of Kufa, Najaf, Iraq
| | | | - Mundher M Mudhafar
- 3 Radiology Department, Jabir Ibn Hayyan Medical University, Najaf, Iraq
| | - Hasan A Al-Nafakh
- 2 Radiology Department, Medicine College, University of Kufa, Najaf, Iraq
| | - Rana Alsaady
- 2 Radiology Department, Medicine College, University of Kufa, Najaf, Iraq
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25
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Kumar S, Voracek M, Singh M. Differential Placing of Flexion Creases Contributes to Sex Differences in the Second-to-Fourth Digit Ratio (2D:4D). Front Endocrinol (Lausanne) 2019; 10:537. [PMID: 31428058 PMCID: PMC6688535 DOI: 10.3389/fendo.2019.00537] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Accepted: 07/18/2019] [Indexed: 12/29/2022] Open
Abstract
The present research examined whether differential placing of the basal flexion creases contributes to the occurrence of sex differences in digit ratio (2D:4D) derived from palmar digit lengths. The ratio of palmar-to-dorsal digit length, a measure of the placing of the basal flexion crease in the finger, was derived for the digits 2 and 4 of the right hand in two independent samples (Study I: N = 100; Study II: N = 200), in accordance with discovery-replication sample approach. The results show that men have lower palmar-to-dorsal digit ratios than women, and this effect is significantly stronger for digit 2 than for digit 4. Thus, the present study supports the likelihood that differential placing of flexion creases in the digits contributes to the occurrence of sex differences in palmar 2D:4D. In addition (Study II), the measurement procedure assessing the placing of flexion creases was validated. In conclusion, this evidence highlights potential conceptual shortcomings and technical limitations in the measurement conventions and methods currently employed in the field of 2D:4D research.
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Affiliation(s)
- Sanjay Kumar
- Department of Psychology, D.A.V. College, Muzaffarnagar, India
- *Correspondence: Sanjay Kumar
| | - Martin Voracek
- Department of Basic Psychological Research and Research Methods, Faculty of Psychology, University of Vienna, Vienna, Austria
- Martin Voracek
| | - Maharaj Singh
- Department of Research and Graduate Studies, School of Dentistry, Marquette University, Milwaukee, WI, United States
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26
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Kociuba M, Chakraborty R, Ignasiak Z, Kozieł S. Digit ratio (2D:4D) moderates the change in handgrip strength on an aggressive stimulus: A study among Polish young adults. Early Hum Dev 2019; 128:62-68. [PMID: 30530102 DOI: 10.1016/j.earlhumdev.2018.11.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Revised: 11/29/2018] [Accepted: 11/30/2018] [Indexed: 02/03/2023]
Abstract
BACKGROUND The ratio of the lengths of second finger (2D) to the fourth (4D) is a putative indicator of foetal hormonal exposure. The link between 2D:4D and physical strength or sports performance in not consistent. It was suggested that the association of 2D:4D with the sporting and physical ability is better demonstrated in the context of challenge and competition, either real or simulated. However the evidence is limited to a few studies till date. AIM The objective of this study was to assess whether an aggressive video show could increase muscular strength and if 2D:4D moderated such increase. STUDY DESIGN We compared outcome measures in two experimental conditions. OUTCOME MEASURES Lengths of second (2D) and fourth (4D) digits and their ratio (2D:4D) for both hands, height and weight, handgrip strength of both hands. SUBJECTS 250 healthy young adults (76 female). RESULTS The mean left-, right- and average HGS values increased after aggressive video watching than after control blank screen show. The increase was higher in females compared to males. The increase was higher among the individuals with lower 2D:4D, more clearly among females. CONCLUSIONS The 2D:4D correlated negatively with HGS after exposure to challenge condition and this relationship is pronounced in females than males. Thus there is link between prenatal androgenisation and enhanced physical power in challenge situation.
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Affiliation(s)
- Marek Kociuba
- General Tadeusz Kosciuszko Military Academy of Land Forces, Wroclaw, Poland
| | - Raja Chakraborty
- Department of Anthropology, Dinabandhu Mahavidyalaya, Bongaon, West Bengal, India
| | - Zofia Ignasiak
- Faculty of Physical Education, University School of Physical Education in Wroclaw, Wroclaw, Poland
| | - Sławomir Kozieł
- Department of Anthropology, Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wroclaw, Poland.
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27
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Shere M, Arbuckle TE, Monnier P, Fraser W, Velez MP. Time-to-pregnancy and offspring finger-length ratio (2D:4D). Am J Hum Biol 2018; 30:e23176. [PMID: 30329191 DOI: 10.1002/ajhb.23176] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Revised: 06/28/2018] [Accepted: 08/01/2018] [Indexed: 12/20/2022] Open
Abstract
OBJECTIVES Time-to-Pregnancy (TTP) is an epidemiological tool to assess couple fecundity. The finger digit ratio (2D:4D) has been suggested as a marker of androgen exposure in utero. Maternal, paternal, or couple-mediated factors related to fecundity may also have an effect on androgen exposure during pregnancy. We aimed to investigate the association between TTP, infertility, or use of Assisted Reproductive Technologies (ART) and offspring 2D:4D. METHODS Data from 673 mother-child pairs were collected from questionnaires in the Maternal-Infant Research on Environmental Chemicals (MIREC) study across 10 cities in Canada. The mean maternal age was 33.4 years (SD 4.7), with a median gestational age of 12.1 weeks (SD 1.3), at the time of recruitment. Our study included 338 girls and 335 boys, and the mean age of the children at follow-up was 3.5 years (SD 1.0). TTP was assessed through questionnaires during the first trimester of pregnancy. Digital photographs of both hands were taken in a follow-up study to calculate the children's 2D:4D (2-5 years). anova, t tests, and multiple linear regression analyses were conducted. RESULTS Boys had significantly lower mean 2D:4Ds (0.936 ±0.041 in right hand, 0.936 ±0.040 in left hand) compared to girls (0.948 ±0.038 in right hand, 0.945 ±0.038 in left hand). The mean 2D:4D did not differ according to TTP, infertility, or use of ART. The only factors associated with the child's 2D:4D were the child's age and maternal 2D:4D. CONCLUSIONS Our study does not support an association between TTP, infertility, or use of ART and children's 2D:4D.
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Affiliation(s)
- Mahvash Shere
- School of Medicine, Queen's University, Kingston, Canada
| | - Tye E Arbuckle
- Targeted Epidemiology and Biomonitoring Section, Environmental Health Science and Research Bureau, Healthy Environments and Consumer Safety Branch, Ottawa, Canada
| | - Patricia Monnier
- Department of Obstetrics and Gynecology, McGill University Health Centre, Montreal, Canada
| | - William Fraser
- Sainte-Justine University Hospital Research Centre, University of Montreal, Montreal, Canada.,Department of Obstetrics and Gynecology, University of Sherbrooke, Quebec, Canada
| | - Maria P Velez
- Department of Obstetrics and Gynaecology, Division of Reproductive Endocrinology and Infertility, Queen's University, Kingston, Canada
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28
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Lombardo MP, Otieno S, Heiss A. College-aged women in the United States that play overhand throwing sports have masculine digit ratios. PLoS One 2018; 13:e0203685. [PMID: 30212523 PMCID: PMC6136748 DOI: 10.1371/journal.pone.0203685] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2017] [Accepted: 08/24/2018] [Indexed: 11/19/2022] Open
Abstract
Athletic prowess in both males and females is negatively correlated with the ratio between the lengths of the second and fourth fingers (2D:4D), a correlate of prenatal testosterone exposure. Because multiple lines of evidence suggest that prenatal testosterone exposure is associated with sports interest, motivation, and athletic performance we measured the digit ratios of 77 non-athletes, 103 varsity athletes, and 78 club sport athletes to test 8 hypotheses about the relationship between digit ratio and the athletic behavior of college-age women in the USA. Using independent samples t-tests, we found no significant differences between the digit ratios of women that (1) were athletes and non-athletes, (2) were varsity or club sport athletes, (3) had played or were currently playing individual or team sports, (4) played contact and non-contact sports, (5) played sports involving a ball and those that do not, (6) played sports where the outcome was determined by a score or the outcome of direct physical competition or subjectively by judges, or (7) were starters or reserves on their teams. However, women that played overhand throwing sports softball and water polo had significantly smaller digit ratios than did women that played other sports. These differences were not due to scaling effects. The independent samples t-test results were supported by subsequent Monte Carlo bootstrap, Bayesian, Random Forest, and multiple linear regression analyses. We suggest that the organizational consequences of prenatal testosterone exposure may influence the anatomy and physiology of women that leads to success playing overhand throwing sports.
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Affiliation(s)
- Michael P. Lombardo
- Biology Department, Grand Valley State University, Allendale, Michigan, United States of America
- * E-mail:
| | - Sango Otieno
- Statistics Department, Grand Valley State University, Allendale, Michigan, United States of America
| | - Adam Heiss
- Statistics Department, Grand Valley State University, Allendale, Michigan, United States of America
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29
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Horn L, Hungerländer NA, Windhager S, Bugnyar T, Massen JJM. Social status and prenatal testosterone exposure assessed via second-to-fourth digit ratio affect 6-9-year-old children's prosocial choices. Sci Rep 2018; 8:9198. [PMID: 29907777 PMCID: PMC6004003 DOI: 10.1038/s41598-018-27468-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Accepted: 05/31/2018] [Indexed: 11/18/2022] Open
Abstract
Prosocial behaviour (i.e., voluntary behaviour intended to benefit another) seems to be fully developed in children by the age of 6 years. However, questions about which factors modify prosocial behaviour at that age remain understudied. Here we used a resource allocation paradigm to test prosocial behaviour in 6-9-year-old school children. They could decide between a "selfish" (i.e., one sticker for themselves) and a "prosocial" option (i.e., one sticker for themselves and one for the receiver) and we tested whether friendship, social status and prenatal androgen exposure (approximated by the 2nd to 4th digit ratio; 2D:4D) influenced children's prosocial choices. We found that children behaved prosocially, and that their prosocial tendencies were negatively correlated with prenatal androgen exposure; i.e., children with high 2D:4D ratios (reflecting low prenatal androgen exposure) acted more prosocially than children with low 2D:4D ratios. Further, their social status in the classroom influenced their choices: children with fewer interaction partners chose the "prosocial" option more often than more 'popular' children. However, they did so irrespectively of whether they were paired with a recipient or not. Our results highlight the importance of considering social, as well as physiological factors when investigating prosocial behaviour in children.
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Affiliation(s)
- Lisa Horn
- Department of Cognitive Biology, University of Vienna, Vienna, Austria.
| | | | - Sonja Windhager
- Department of Anthropology, University of Vienna, Vienna, Austria
- Department of Theoretical Biology, University of Vienna, Vienna, Austria
| | - Thomas Bugnyar
- Department of Cognitive Biology, University of Vienna, Vienna, Austria
| | - Jorg J M Massen
- Department of Cognitive Biology, University of Vienna, Vienna, Austria
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30
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Warrington NM, Shevroja E, Hemani G, Hysi PG, Jiang Y, Auton A, Boer CG, Mangino M, Wang CA, Kemp JP, McMahon G, Medina-Gomez C, Hickey M, Trajanoska K, Wolke D, Ikram MA, Montgomery GW, Felix JF, Wright MJ, Mackey DA, Jaddoe VW, Martin NG, Tung JY, Davey Smith G, Pennell CE, Spector TD, van Meurs J, Rivadeneira F, Medland SE, Evans DM. Genome-wide association study identifies nine novel loci for 2D:4D finger ratio, a putative retrospective biomarker of testosterone exposure in utero. Hum Mol Genet 2018; 27:2025-2038. [PMID: 29659830 PMCID: PMC5961159 DOI: 10.1093/hmg/ddy121] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2017] [Revised: 03/12/2018] [Accepted: 04/03/2018] [Indexed: 02/06/2023] Open
Abstract
The ratio of the length of the index finger to that of the ring finger (2D:4D) is sexually dimorphic and is commonly used as a non-invasive biomarker of prenatal androgen exposure. Most association studies of 2D:4D ratio with a diverse range of sex-specific traits have typically involved small sample sizes and have been difficult to replicate, raising questions around the utility and precise meaning of the measure. In the largest genome-wide association meta-analysis of 2D:4D ratio to date (N = 15 661, with replication N = 75 821), we identified 11 loci (9 novel) explaining 3.8% of the variance in mean 2D:4D ratio. We also found weak evidence for association (β = 0.06; P = 0.02) between 2D:4D ratio and sensitivity to testosterone [length of the CAG microsatellite repeat in the androgen receptor (AR) gene] in females only. Furthermore, genetic variants associated with (adult) testosterone levels and/or sex hormone-binding globulin were not associated with 2D:4D ratio in our sample. Although we were unable to find strong evidence from our genetic study to support the hypothesis that 2D:4D ratio is a direct biomarker of prenatal exposure to androgens in healthy individuals, our findings do not explicitly exclude this possibility, and pathways involving testosterone may become apparent as the size of the discovery sample increases further. Our findings provide new insight into the underlying biology shaping 2D:4D variation in the general population.
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Affiliation(s)
- Nicole M Warrington
- The University of Queensland Diamantina Institute, Translational Research Institute, University of Queensland, Brisbane, QLD 4102, Australia
- Queensland Institute of Medical Research, Brisbane, QLD 4006, Australia
- Division of Obstetrics and Gynaecology, The University of Western Australia, Perth, WA 6009, Australia
| | - Enisa Shevroja
- The Generation R Study Group, Erasmus MC, University Medical Center Rotterdam, 3015 CN, Rotterdam, South Holland, The Netherlands
- Department of Internal Medicine, Erasmus MC, University Medical Center Rotterdam, 3015 CN, Rotterdam, The Netherlands
| | - Gibran Hemani
- MRC Integrative Epidemiology Unit, University of Bristol, Bristol BS8 2BN, UK
- Population Health Sciences, University of Bristol, Bristol BS8 2PS, UK
| | - Pirro G Hysi
- Department of Twin Research and Genetic Epidemiology, King’s College London, London SE1 7EH, UK
| | | | - Adam Auton
- 23andMe, Inc., Mountain View, CA 94061, USA
| | - Cindy G Boer
- Department of Internal Medicine, Erasmus MC, University Medical Center Rotterdam, 3015 CN, Rotterdam, The Netherlands
| | - Massimo Mangino
- Department of Twin Research and Genetic Epidemiology, King’s College London, London SE1 7EH, UK
| | - Carol A Wang
- Division of Obstetrics and Gynaecology, The University of Western Australia, Perth, WA 6009, Australia
- School of Medicine and Public Health, Faculty of Medicine and Health, The University of Newcastle, Newcastle, NSW 2308, Australia
| | - John P Kemp
- The University of Queensland Diamantina Institute, Translational Research Institute, University of Queensland, Brisbane, QLD 4102, Australia
- MRC Integrative Epidemiology Unit, University of Bristol, Bristol BS8 2BN, UK
- Population Health Sciences, University of Bristol, Bristol BS8 2PS, UK
| | - George McMahon
- MRC Integrative Epidemiology Unit, University of Bristol, Bristol BS8 2BN, UK
- Population Health Sciences, University of Bristol, Bristol BS8 2PS, UK
| | - Carolina Medina-Gomez
- The Generation R Study Group, Erasmus MC, University Medical Center Rotterdam, 3015 CN, Rotterdam, South Holland, The Netherlands
- Department of Internal Medicine, Erasmus MC, University Medical Center Rotterdam, 3015 CN, Rotterdam, The Netherlands
- Department of Epidemiology, Erasmus MC, University Medical Center Rotterdam, 3015 CN, Rotterdam, Netherlands
| | - Martha Hickey
- Department of Obstetrics and Gynaecology, The University of Melbourne and the Royal Women’s Hospital, Parkville, VIC 3052, Australia
| | - Katerina Trajanoska
- Department of Internal Medicine, Erasmus MC, University Medical Center Rotterdam, 3015 CN, Rotterdam, The Netherlands
- Department of Epidemiology, Erasmus MC, University Medical Center Rotterdam, 3015 CN, Rotterdam, Netherlands
| | - Dieter Wolke
- Department of Psychology and Warwick Medical School, University of Warwick, Coventry CV47AL, UK
| | - M Arfan Ikram
- Department of Epidemiology, Erasmus MC, University Medical Center Rotterdam, 3015 CN, Rotterdam, Netherlands
| | | | - Grant W Montgomery
- Queensland Brain Institute and Centre for Advanced Imaging, University of Queensland, Brisbane, QLD 4072, Australia
| | - Janine F Felix
- The Generation R Study Group, Erasmus MC, University Medical Center Rotterdam, 3015 CN, Rotterdam, South Holland, The Netherlands
- Department of Epidemiology, Erasmus MC, University Medical Center Rotterdam, 3015 CN, Rotterdam, Netherlands
- Department of Pediatrics, Erasmus MC, University Medical Center Rotterdam, 3015 CN, Rotterdam, The Netherlands
| | - Margaret J Wright
- Queensland Brain Institute and Centre for Advanced Imaging, University of Queensland, Brisbane, QLD 4072, Australia
| | - David A Mackey
- Lions Eye Institute, Centre for Ophthalmology and Visual Science, The University of Western Australia, Perth, WA 6009, Australia
| | - Vincent W Jaddoe
- The Generation R Study Group, Erasmus MC, University Medical Center Rotterdam, 3015 CN, Rotterdam, South Holland, The Netherlands
- Department of Epidemiology, Erasmus MC, University Medical Center Rotterdam, 3015 CN, Rotterdam, Netherlands
- Department of Pediatrics, Erasmus MC, University Medical Center Rotterdam, 3015 CN, Rotterdam, The Netherlands
| | - Nicholas G Martin
- Queensland Institute of Medical Research, Brisbane, QLD 4006, Australia
| | | | - George Davey Smith
- MRC Integrative Epidemiology Unit, University of Bristol, Bristol BS8 2BN, UK
- Population Health Sciences, University of Bristol, Bristol BS8 2PS, UK
| | - Craig E Pennell
- Division of Obstetrics and Gynaecology, The University of Western Australia, Perth, WA 6009, Australia
- School of Medicine and Public Health, Faculty of Medicine and Health, The University of Newcastle, Newcastle, NSW 2308, Australia
| | - Tim D Spector
- Department of Twin Research and Genetic Epidemiology, King’s College London, London SE1 7EH, UK
| | - Joyce van Meurs
- The Generation R Study Group, Erasmus MC, University Medical Center Rotterdam, 3015 CN, Rotterdam, South Holland, The Netherlands
| | - Fernando Rivadeneira
- The Generation R Study Group, Erasmus MC, University Medical Center Rotterdam, 3015 CN, Rotterdam, South Holland, The Netherlands
- Department of Internal Medicine, Erasmus MC, University Medical Center Rotterdam, 3015 CN, Rotterdam, The Netherlands
- Department of Epidemiology, Erasmus MC, University Medical Center Rotterdam, 3015 CN, Rotterdam, Netherlands
| | - Sarah E Medland
- Queensland Institute of Medical Research, Brisbane, QLD 4006, Australia
| | - David M Evans
- The University of Queensland Diamantina Institute, Translational Research Institute, University of Queensland, Brisbane, QLD 4102, Australia
- MRC Integrative Epidemiology Unit, University of Bristol, Bristol BS8 2BN, UK
- Population Health Sciences, University of Bristol, Bristol BS8 2PS, UK
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31
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Warrington NM, Shevroja E, Hemani G, Hysi PG, Jiang Y, Auton A, Boer CG, Mangino M, Wang CA, Kemp JP, McMahon G, Medina-Gomez C, Hickey M, Trajanoska K, Wolke D, Ikram MA, Montgomery GW, Felix JF, Wright MJ, Mackey DA, Jaddoe VW, Martin NG, Tung JY, Davey Smith G, Pennell CE, Spector TD, van Meurs J, Rivadeneira F, Medland SE, Evans DM. Genome-wide association study identifies nine novel loci for 2D:4D finger ratio, a putative retrospective biomarker of testosterone exposure in utero. Hum Mol Genet 2018; 27:2025-2038. [PMID: 29659830 PMCID: PMC5961159 DOI: 10.1093/hmg/ddy121 10.1093/hmg/ddy121] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2017] [Revised: 03/12/2018] [Accepted: 04/03/2018] [Indexed: 10/22/2023] Open
Abstract
The ratio of the length of the index finger to that of the ring finger (2D:4D) is sexually dimorphic and is commonly used as a non-invasive biomarker of prenatal androgen exposure. Most association studies of 2D:4D ratio with a diverse range of sex-specific traits have typically involved small sample sizes and have been difficult to replicate, raising questions around the utility and precise meaning of the measure. In the largest genome-wide association meta-analysis of 2D:4D ratio to date (N = 15 661, with replication N = 75 821), we identified 11 loci (9 novel) explaining 3.8% of the variance in mean 2D:4D ratio. We also found weak evidence for association (β = 0.06; P = 0.02) between 2D:4D ratio and sensitivity to testosterone [length of the CAG microsatellite repeat in the androgen receptor (AR) gene] in females only. Furthermore, genetic variants associated with (adult) testosterone levels and/or sex hormone-binding globulin were not associated with 2D:4D ratio in our sample. Although we were unable to find strong evidence from our genetic study to support the hypothesis that 2D:4D ratio is a direct biomarker of prenatal exposure to androgens in healthy individuals, our findings do not explicitly exclude this possibility, and pathways involving testosterone may become apparent as the size of the discovery sample increases further. Our findings provide new insight into the underlying biology shaping 2D:4D variation in the general population.
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Affiliation(s)
- Nicole M Warrington
- The University of Queensland Diamantina Institute, Translational Research Institute, University of Queensland, Brisbane, QLD 4102, Australia
- Queensland Institute of Medical Research, Brisbane, QLD 4006, Australia
- Division of Obstetrics and Gynaecology, The University of Western Australia, Perth, WA 6009, Australia
| | - Enisa Shevroja
- The Generation R Study Group, Erasmus MC, University Medical Center Rotterdam, 3015 CN, Rotterdam, South Holland, The Netherlands
- Department of Internal Medicine, Erasmus MC, University Medical Center Rotterdam, 3015 CN, Rotterdam, The Netherlands
| | - Gibran Hemani
- MRC Integrative Epidemiology Unit, University of Bristol, Bristol BS8 2BN, UK
- Population Health Sciences, University of Bristol, Bristol BS8 2PS, UK
| | - Pirro G Hysi
- Department of Twin Research and Genetic Epidemiology, King’s College London, London SE1 7EH, UK
| | | | - Adam Auton
- 23andMe, Inc., Mountain View, CA 94061, USA
| | - Cindy G Boer
- Department of Internal Medicine, Erasmus MC, University Medical Center Rotterdam, 3015 CN, Rotterdam, The Netherlands
| | - Massimo Mangino
- Department of Twin Research and Genetic Epidemiology, King’s College London, London SE1 7EH, UK
| | - Carol A Wang
- Division of Obstetrics and Gynaecology, The University of Western Australia, Perth, WA 6009, Australia
- School of Medicine and Public Health, Faculty of Medicine and Health, The University of Newcastle, Newcastle, NSW 2308, Australia
| | - John P Kemp
- The University of Queensland Diamantina Institute, Translational Research Institute, University of Queensland, Brisbane, QLD 4102, Australia
- MRC Integrative Epidemiology Unit, University of Bristol, Bristol BS8 2BN, UK
- Population Health Sciences, University of Bristol, Bristol BS8 2PS, UK
| | - George McMahon
- MRC Integrative Epidemiology Unit, University of Bristol, Bristol BS8 2BN, UK
- Population Health Sciences, University of Bristol, Bristol BS8 2PS, UK
| | - Carolina Medina-Gomez
- The Generation R Study Group, Erasmus MC, University Medical Center Rotterdam, 3015 CN, Rotterdam, South Holland, The Netherlands
- Department of Internal Medicine, Erasmus MC, University Medical Center Rotterdam, 3015 CN, Rotterdam, The Netherlands
- Department of Epidemiology, Erasmus MC, University Medical Center Rotterdam, 3015 CN, Rotterdam, Netherlands
| | - Martha Hickey
- Department of Obstetrics and Gynaecology, The University of Melbourne and the Royal Women’s Hospital, Parkville, VIC 3052, Australia
| | - Katerina Trajanoska
- Department of Internal Medicine, Erasmus MC, University Medical Center Rotterdam, 3015 CN, Rotterdam, The Netherlands
- Department of Epidemiology, Erasmus MC, University Medical Center Rotterdam, 3015 CN, Rotterdam, Netherlands
| | - Dieter Wolke
- Department of Psychology and Warwick Medical School, University of Warwick, Coventry CV47AL, UK
| | - M Arfan Ikram
- Department of Epidemiology, Erasmus MC, University Medical Center Rotterdam, 3015 CN, Rotterdam, Netherlands
| | | | - Grant W Montgomery
- Queensland Brain Institute and Centre for Advanced Imaging, University of Queensland, Brisbane, QLD 4072, Australia
| | - Janine F Felix
- The Generation R Study Group, Erasmus MC, University Medical Center Rotterdam, 3015 CN, Rotterdam, South Holland, The Netherlands
- Department of Epidemiology, Erasmus MC, University Medical Center Rotterdam, 3015 CN, Rotterdam, Netherlands
- Department of Pediatrics, Erasmus MC, University Medical Center Rotterdam, 3015 CN, Rotterdam, The Netherlands
| | - Margaret J Wright
- Queensland Brain Institute and Centre for Advanced Imaging, University of Queensland, Brisbane, QLD 4072, Australia
| | - David A Mackey
- Lions Eye Institute, Centre for Ophthalmology and Visual Science, The University of Western Australia, Perth, WA 6009, Australia
| | - Vincent W Jaddoe
- The Generation R Study Group, Erasmus MC, University Medical Center Rotterdam, 3015 CN, Rotterdam, South Holland, The Netherlands
- Department of Epidemiology, Erasmus MC, University Medical Center Rotterdam, 3015 CN, Rotterdam, Netherlands
- Department of Pediatrics, Erasmus MC, University Medical Center Rotterdam, 3015 CN, Rotterdam, The Netherlands
| | - Nicholas G Martin
- Queensland Institute of Medical Research, Brisbane, QLD 4006, Australia
| | | | - George Davey Smith
- MRC Integrative Epidemiology Unit, University of Bristol, Bristol BS8 2BN, UK
- Population Health Sciences, University of Bristol, Bristol BS8 2PS, UK
| | - Craig E Pennell
- Division of Obstetrics and Gynaecology, The University of Western Australia, Perth, WA 6009, Australia
- School of Medicine and Public Health, Faculty of Medicine and Health, The University of Newcastle, Newcastle, NSW 2308, Australia
| | - Tim D Spector
- Department of Twin Research and Genetic Epidemiology, King’s College London, London SE1 7EH, UK
| | - Joyce van Meurs
- The Generation R Study Group, Erasmus MC, University Medical Center Rotterdam, 3015 CN, Rotterdam, South Holland, The Netherlands
| | - Fernando Rivadeneira
- The Generation R Study Group, Erasmus MC, University Medical Center Rotterdam, 3015 CN, Rotterdam, South Holland, The Netherlands
- Department of Internal Medicine, Erasmus MC, University Medical Center Rotterdam, 3015 CN, Rotterdam, The Netherlands
- Department of Epidemiology, Erasmus MC, University Medical Center Rotterdam, 3015 CN, Rotterdam, Netherlands
| | - Sarah E Medland
- Queensland Institute of Medical Research, Brisbane, QLD 4006, Australia
| | - David M Evans
- The University of Queensland Diamantina Institute, Translational Research Institute, University of Queensland, Brisbane, QLD 4102, Australia
- MRC Integrative Epidemiology Unit, University of Bristol, Bristol BS8 2BN, UK
- Population Health Sciences, University of Bristol, Bristol BS8 2PS, UK
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Gooding DC, Chambers BH. Age of pubertal onset and 2nd to 4th digit ratios: Preliminary findings. Early Hum Dev 2018; 116:28-32. [PMID: 29112888 DOI: 10.1016/j.earlhumdev.2017.10.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Revised: 10/23/2017] [Accepted: 10/30/2017] [Indexed: 11/17/2022]
Abstract
BACKGROUND The second to fourth digit ratio (2D:4D) is used as a marker of prenatal sex hormone exposure. The aim of this study was to evaluate the possible relation between digit ratio and age of pubertal onset. METHODS Participants were 321 men and 202 women aged between 18 and 28 at the time of assessment who self-reported their onset of puberty (i.e., age at first conscious ejaculation or menarche). Participants' right and left digit lengths were measured from hand scans. RESULTS All groups of males, i.e., early, average, and late pubertal onset, had lower mean 2D:4D than the comparable female groups, regardless of the relative timing of their pubertal onset. Among the males, there was a significant difference in digit ratios between individuals who experienced early, average, and late onset of puberty. In the males, we observed a positive relationship between 2D:4D and age of pubertal onset for both right and left hands. There were no significant differences in 2D:4D among the three groups of female maturers. We observed no significant association between digit ratios and age at menarche. CONCLUSIONS These data lend further support for using 2D:4D as a measure of prenatal androgen exposure.
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Affiliation(s)
- Diane C Gooding
- Department of Psychology, University of Wisconsin, Madison WI, USA.
| | - Blake H Chambers
- Department of Psychology, University of Wisconsin, Madison WI, USA
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Keshavarz M, Bayati M, Farzad B, Dakhili A, Agha-Alinejad H. The Second to Fourth Digit Ratio in Elite and Non-Elite Greco-Roman Wrestlers. J Hum Kinet 2017; 60:145-151. [PMID: 29339994 PMCID: PMC5765794 DOI: 10.1515/hukin-2017-0097] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
A low second-to-fourth digit ratio (2D:4D) has been reported to correlate with high performance and athletic potential of an individual in sport. It has been suggested that 2D:4D is a relatively weak predictor of strength and a stronger predictor of efficiency in aerobic exercise. Comparing extreme groups on a continuum of sports performance requiring high power (physical strength) output would be helpful to resolve this issue. Therefore, the purpose of the present study was to compare the 2D:4D ratio of world-class elite Greco-Roman wrestlers (n = 10) taking part in Olympic fitness camps in 2013 with the 2D:4D ratio of non-elite collegiate wrestlers (n = 20), and age-matched sedentary males (n = 40). The 2D:4D ratios of elite wrestlers were lower compared to non-elite athletes (p < 0.01, right hand d = 1.70, left hand d = 1.67) and the control group (p < 0.0001, right hand d = 3.16, left hand d = 2.00). No significant differences were noted among the groups for right - left 2D:4D. We concluded that 2D:4D may discriminate between non-elite and world-class wrestlers. We also suggest that a low 2D:4D ratio could be linked to performance potential in wrestlers. As such, 2D:4D may provide additional information, which is valuable in determining the potential athleticism of an individual, when it is used in conjunction with other measures.
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Affiliation(s)
- Mohammad Keshavarz
- Department of Physical Education, Faculty of Humanities, Tarbiat Modares University, Tehran, Iran
- Mohammad Keshavarz Department of Physical Education, Faculty of Humanities, Tarbiat Modares University. Jalal AleAhmad Highway, Nasr Bridge, Tehran, Iran. Phone number: +98 912 759 3799
| | - Mahdi Bayati
- Department of Exercise Physiology, Sports Medicine Research Center, Sport Sciences Research Institute, Tehran, Iran
| | - Babak Farzad
- Neuroscience Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Amirbahador Dakhili
- Department of Physical Education, Faculty of Humanities, Tarbiat Modares University, Tehran, Iran
| | - Hamid Agha-Alinejad
- Department of Physical Education, Faculty of Humanities, Tarbiat Modares University, Tehran, Iran
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Kaneoke Y, Donishi T, Iwahara A, Shimokawa T. Severity of Premenstrual Symptoms Predicted by Second to Fourth Digit Ratio. Front Med (Lausanne) 2017; 4:144. [PMID: 28936432 PMCID: PMC5595152 DOI: 10.3389/fmed.2017.00144] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Accepted: 08/14/2017] [Indexed: 12/25/2022] Open
Abstract
Women of reproductive age often experience a variety of unpleasant symptoms prior to the onset of menstruation. While genetics may influence the variability of these symptoms and their severity among women, the exact causes remain unknown. We hypothesized that symptom variability originates from differences in the embryonic environment and thus development caused by variation in exposure to sex hormones. We measured the second to fourth digit ratios (2D:4D) in 402 young women and investigated the potential relationships of this ratio premenstrual symptoms using a generalized linear model. We found that two models (one with two predictors such as both hands' digit ratios and the other with the difference between the two digit ratios, Dr-l) were significantly different from the constant model as assessed by chi-square test. The right digit ratio and Dr-l were negatively related to the symptom scores, and the left digit ratio was related to the scores. When premenstrual symptoms were classified into eight categories, five categories, including pain, concentration, autonomic reaction, negative affect, and control were associated with the digit ratios and Dr-l. Behavioral changes and water retention were not predicted by them. Arousal was predicted by Dr-l. The right 2D:4D is thought to be determined by the balance of testosterone and estrogen levels during early embryogenesis and is not affected by postpartum levels of sex hormones, while the left 2D:4D might be affected by the other prenatal environmental factors. We conclude that the embryonic environment, including the relative concentration of sex hormones an embryo is exposed to, is associated with the severity of premenstrual symptoms once menarche is reached.
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Affiliation(s)
- Yoshiki Kaneoke
- Department of System Neurophysiology, Wakayama Medical University, Wakayama, Japan
| | - Tomohiro Donishi
- Department of System Neurophysiology, Wakayama Medical University, Wakayama, Japan
| | - Akihiko Iwahara
- School of Health and Nursing Science, Wakayama Medical University, Wakayama, Japan
| | - Toshio Shimokawa
- Clinical Research Center, Wakayama Medical University, Wakayama, Japan
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Familial digit ratio (2D:4D) associations in a general population sample from Wales. Early Hum Dev 2017; 112:14-19. [PMID: 28668648 PMCID: PMC5566275 DOI: 10.1016/j.earlhumdev.2017.06.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Revised: 06/13/2017] [Accepted: 06/20/2017] [Indexed: 11/30/2022]
Abstract
BACKGROUND The relative length of the second and fourth fingers (2D:4D) may be a sex-linked correlate of prenatal androgen exposure. However, the nature of the sex-linkage is controversial, with evidence for both X- and Y-linkage of the 2D:4D phenotype. AIMS To examine transgenerational effects relating to sex-linkage. In addition, assortative mating on 2D:4D was considered, as well as associations between 2D:4D and age and sex. STUDY DESIGN A family study was conducted. Parents and offspring completed a demographic questionnaire, and digit ratios were calculated from photocopies of participants' hands. SUBJECTS We recruited and phenotyped 585 individuals attending a cultural festival in Wales. 2D:4D information was available for 47 mother-son dyads, 70 mother-daughter dyads, 31 father-son dyads and 30 father-daughter dyads. OUTCOME MEASURES Correlations between 2D:4D of parents and children, as well as between mothers and fathers were conducted. 2D:4D was also examined in relation to age and sex. RESULTS AND CONCLUSIONS There was a sex difference in 2D:4D (males<females). Within the dyads, there was a significant positive correlation between mother and daughter 2D:4D, but no significant correlation between mother and son ratios, nor between father and offspring ratios. The overall pattern of correlations (with emphasis on father-son dyads) was not supportive of Y-linkage. There was a positive correlation between 2D:4D and age in children, and a negative correlation between 2D:4D and age in adults, and no evidence of assortative mating. Our data are consistent with the notion of 2D:4D as a sexually-dimorphic, mildly age-sensitive, and transgenerationally-transmitted trait that is more likely to be X- than Y-linked.
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FURTHER EVIDENCE OF AN ASSOCIATION BETWEEN LOW SECOND-TO-FOURTH DIGIT RATIO (2D:4D) AND SELECTION FOR THE UNIFORMED SERVICES: A STUDY AMONG POLICE PERSONNEL IN WROCŁAW, POLAND. J Biosoc Sci 2017; 50:527-539. [PMID: 28828996 DOI: 10.1017/s0021932017000438] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Males and females differ in their preference for occupations and sporting activities, and differ also in risk-taking attitudes. In addition to other explanations, prenatal hormone exposure has been implicated in these gender-associated differences. The ratio of the relative lengths of the second-to-fourth digits (2D:4D) is a proxy indicator of prenatal exposure to testosterone relative to oestrogen. The 2D:4D ratio has been found to be associated with choice of occupation, particularly among females. This study investigated whether 2D:4D differed between police officers and a control group of civilians in Wrocław, Poland. Participants were 147 male and 55 female police officers and 91 male and 75 female civilian controls. The police officers had to undergo rigorous physical ability tests during recruitment and their job bore relatively higher risk, whereas the controls had a normal civilian lifestyle. Height, weight, hand grip strength and lengths of the second and fourth digits were measured. Analyses of variance and covariance were employed to assess the significance of difference in digit ratio between groups (police officers and civilians) allowing for interaction with sex. The policewomen, compared with the female controls, were taller and had stronger hand grip strength, but had lower 2D:4D in the right hand and average 2D:4D of both hands. However, male and female police officers slightly differed only in the right hand digit ratio but not in the left hand ratio or the average for the two hands. However, the control group showed significant sex differences in all digit ratios with higher (feminine) mean values in females. The study provides further evidence that prenatal testosterone exposure, as reflected in the 2D:4D ratio, might have an association with choice of occupation, particularly among females.
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Yokoi T, Uemura T, Kazuki K, Onode E, Shintani K, Okada M, Nakamura H. Low second to fourth digit ratio in Dupuytren disease. Medicine (Baltimore) 2017; 96:e7801. [PMID: 28816972 PMCID: PMC5571709 DOI: 10.1097/md.0000000000007801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
The ratio of the lengths of the second and fourth digits (2D:4D) has been described as reflecting endogenous prenatal androgen exposure. In general, 2D:4D is lower in men than in women and has potential as a biomarker or predictor for various diseases, athletic ability, and academic performance. Dupuytren disease has digital flexion contractures and is known to predominate in men, but the pathogenesis of the disease remains unclear. To clarify the relationships between Dupuytren disease and endogenous androgens, we performed a retrospective analysis of hand radiographs to investigate 2D:4D in Dupuytren disease. The study included male patients with Dupuytren disease (n = 22) and a control group (n = 18) of male patients with carpal tunnel syndrome. Only unaffected hands, without contractures or osteoarthritis, were evaluated for the purpose of radiographic assessment. The lengths of the phalanx and metacarpal bones in the second and fourth digits were measured by 2 independent observers who each performed 2 sets of measurements separated by a minimum 1-week interval. The 2D:4D was calculated separately for the phalanges and metacarpals, and a combined (phalanx + metacarpal) 2D:4D was also calculated. The reliability of the observer measurements was established using the intraclass correlation coefficient, and both the intra- and interobserver reliability showed excellent agreement. We found that compared with control group, the Dupuytren disease group had significantly lower phalanx and combined 2D:4D. These findings suggest that endogenous prenatal androgens could contribute to the development of Dupuytren disease, leading to its characteristic clinical presentation predominantly in men and affecting the ulnar rays.
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Affiliation(s)
- Takuya Yokoi
- Department of Orthopaedic Surgery, Osaka City University Graduate School of Medicine, Osaka
| | - Takuya Uemura
- Department of Orthopaedic Surgery, Osaka City University Graduate School of Medicine, Osaka
| | | | - Ema Onode
- Department of Orthopaedic Surgery, Osaka City University Graduate School of Medicine, Osaka
| | - Kosuke Shintani
- Department of Orthopaedic Surgery, Osaka City University Graduate School of Medicine, Osaka
| | - Mitsuhiro Okada
- Department of Orthopaedic Surgery, Osaka City University Graduate School of Medicine, Osaka
| | - Hiroaki Nakamura
- Department of Orthopaedic Surgery, Osaka City University Graduate School of Medicine, Osaka
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Kasielska-Trojan A, Stabryła P, Antoszewski B. Digit ratio (2D:4D) and postoperative pain perception. Early Hum Dev 2017; 110:25-30. [PMID: 28499134 DOI: 10.1016/j.earlhumdev.2017.05.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Revised: 05/01/2017] [Accepted: 05/02/2017] [Indexed: 11/15/2022]
Abstract
BACKGROUNDS It has not been established whether sex differences in pain perception are influenced by prenatal sex hormones. Digit ratio as an indicator of prenatal hormone exposure can be used as a simple measure of the influence of prenatal hormones on pain sensitivity or perception in adulthood. OBJECTIVE The aim of this study was to determine a correlation between the 2D:4D ratio and pain perception in the postoperative period after rhinoplasty. METHOD A prospective cohort study of 100 patients (50 women of the mean age of 30.74±8.09years and 50 men of the mean age of 30.98±10.86years) who underwent posttraumatic rhinoplasty due to the nose trauma in Plastic, Reconstructive and Aesthetic Surgery Clinic. The following measurements were taken the day before a surgery: body height, waist and hip circumference, II and IV digits' lengths and body weight. All subjects filled in a questionnaire including 0-10-point VAS scales to assess postoperative pain 1h after an operation (AO), 6h AO, 12h AO, 24h AO and 48h AO. RESULTS Women with low 2D:4D reported significantly more pain 1h after an operation than women with high 2D:4D. Similar correlation was observed for low 2D:4D in women 48h AO. In men, low 2D:4D was associated with lower postoperative pain 12h AO (p=0.029). CONCLUSION In conclusion, we showed that low 2D:4D in women was associated with high postoperative pain, and low right 2D:4D in men was associated with low postoperative pain. This may suggest that intrauterine estrogen exposure makes women more resistant to pain.
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Affiliation(s)
- Anna Kasielska-Trojan
- Plastic, Reconstructive and Aesthetic Surgery Clinic, University Hospital No 1 in Lodz, Lodz, Poland; Plastic, Reconstructive and Aesthetic Surgery Clinic, Institute of Surgery, Medical University of Lodz, Lodz, Poland.
| | - Piotr Stabryła
- Plastic, Reconstructive and Aesthetic Surgery Clinic, University Hospital No 1 in Lodz, Lodz, Poland
| | - Bogusław Antoszewski
- Plastic, Reconstructive and Aesthetic Surgery Clinic, University Hospital No 1 in Lodz, Lodz, Poland; Plastic, Reconstructive and Aesthetic Surgery Clinic, Institute of Surgery, Medical University of Lodz, Lodz, Poland
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Is maternal periconceptional smoking associated with 2D:4D digit ratio in their children? J Dev Orig Health Dis 2017; 8:597-603. [DOI: 10.1017/s2040174417000320] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The 2nd--4th finger ratio (2D:4D) has been proposed as a potential indicator of greater androgen exposure during fetal development. Maternal periconceptional smoking may alter the homeostasis of fetal androgens, which could in turn result in differential development of 2D:4Ds in utero. The aim of the present study was to assess the effect of maternal periconceptional smoking (i.e. 1 year before through the first trimester of pregnancy) on the 2D:4D of children within The Maternal-Infant Research on Environmental Chemicals (MIREC) study. Maternal smoking history was obtained through questionnaires during the first trimester of pregnancy in 2001 women from 10 cities across Canada. The periconceptional smoking prevalence was 12%. A follow-up study was conducted to measure growth and development up to 5 years of age in a subsample of some 800 MIREC children (MIREC-CD Plus), and digital pictures of the ventral surface of both hands were obtained in mothers and children (2–5 years). The 2D:4D was calculated as the ratio of the 2nd and 4th fingers of each hand. Boys had lower mean 2D:4Ds compared with girls in both hands. Age and maternal 2D:4D were strong determinants of the children’s 2D:4D, however, the mean 2D:4D did not differ among children whose mothers had smoked during the periconceptional period compared with those who had not, irrespective of sex. In conclusion, we did not find an association between maternal periconceptional smoking and children’s 2D:4D, although the smoking prevalence was low.
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Hoskin AW. Male sex hormones and criminal behavior: The predictive power of a two-factor model of organizational androgen exposure. PERSONALITY AND INDIVIDUAL DIFFERENCES 2017. [DOI: 10.1016/j.paid.2016.11.034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Kusev P, Purser H, Heilman R, Cooke AJ, Van Schaik P, Baranova V, Martin R, Ayton P. Understanding Risky Behavior: The Influence of Cognitive, Emotional and Hormonal Factors on Decision-Making under Risk. Front Psychol 2017; 8:102. [PMID: 28203215 PMCID: PMC5285332 DOI: 10.3389/fpsyg.2017.00102] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2016] [Accepted: 01/16/2017] [Indexed: 11/24/2022] Open
Abstract
Financial risky decisions and evaluations pervade many human everyday activities. Scientific research in such decision-making typically explores the influence of socio-economic and cognitive factors on financial behavior. However, very little research has explored the holistic influence of contextual, emotional, and hormonal factors on preferences for risk in insurance and investment behaviors. Accordingly, the goal of this review article is to address the complexity of individual risky behavior and its underlying psychological factors, as well as to critically examine current regulations on financial behavior.
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Affiliation(s)
- Petko Kusev
- Department of Psychology, Kingston University London London, UK
| | - Harry Purser
- Department of Psychology, Nottingham Trent University Nottingham, UK
| | - Renata Heilman
- Department of Psychology, Babeş-Bolyai University Cluj-Napoca, Romania
| | - Alex J Cooke
- Department of Psychology, Kingston University London London, UK
| | - Paul Van Schaik
- Department of Psychology, Teesside University Middlesbrough, UK
| | - Victoria Baranova
- Department of Psychology, Lomonosov Moscow State University Moscow, Russia
| | - Rose Martin
- Department of Psychology, Kingston University London London, UK
| | - Peter Ayton
- Department of Psychology, City University of London London, UK
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Králík M, Ingrová P, Kozieł S, Hupková A, Klíma O. Overall trends vs. individual trajectories in the second-to-fourth digit (2D:4D) and metacarpal (2M:4M) ratios during puberty and adolescence. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2017; 162:641-656. [PMID: 28121011 DOI: 10.1002/ajpa.23153] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Revised: 11/23/2016] [Accepted: 12/02/2016] [Indexed: 01/12/2023]
Abstract
OBJECTIVES The second-to-fourth digit ratio (2D:4D ratio) can be assumed a valid indicator of sexual differentiation, provided that it is stable once it develops, or eventual changes remain uniform in a respective cohort throughout ontogenesis. The main goal of this study was to determine whether the metacarpal 2M:4M and the digit 2D:4D ratio change during the period of pubertal/adolescent growth. MATERIALS AND METHODS The metacarpals and digits were measured on radiographs of left hands in the sample of 328 individuals (96 pairs of male and 68 pairs of female twins) from the Wrocław Longitudinal Study of Twins (1967-1983). Five consecutive annual measurements were done for each individual within a 4-year-interval somewhere between 7 and 18 years of age. Age-related changes in both ratios were studied using a set of mixed-effects linear models. Three types of correlation coefficients were used for assessment of stability between repeated measurements at different ages. RESULTS An overall decrease in the average 2M:4M ratio was observed, attributable to a much larger extent to males than to females. On the contrary, a slight overall increase in the average 2D:4D ratio was observed, attributable to a much larger extent to females than to males. The rank order of the ratios remained highly stable within the monitored period (the correlation coefficient mostly ranged between 0.85 and 0.95). In spite of these findings, we recorded significant intraindividual changes in both ratios. In some individuals the 2D:4D ratio can undergo changes comparable to average sex differences and much higher than average age-related changes. DISCUSSION Relatively slight overall changes in digit ratio in puberty and adolescence themselves are not inconsistent with the use of the 2D:4D ratio as an indirect marker of prenatal sexual differentiation. Nevertheless, individual changes in the ratios varied substantially in this study and differed from the average trends. Future studies should focus on the nature of interindividual developmental differences in the digit and metacarpal ratios.
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Affiliation(s)
- Miroslav Králík
- Masaryk University, Faculty of Science, Department of Anthropology, Laboratory of Morphology and Forensic Anthropology, Kotlářská 2, Brno, 611 37, Czech Republic
| | - Pavlína Ingrová
- Masaryk University, Faculty of Science, Department of Anthropology, Laboratory of Morphology and Forensic Anthropology, Kotlářská 2, Brno, 611 37, Czech Republic
| | - Sławomir Kozieł
- Polish Academy of Sciences, Hirszfeld Institute of Immunology and Experimental Therapy, Department of Anthropology, Podwale 75, Wrocław, 50-449, Poland
| | - Adela Hupková
- Masaryk University, Faculty of Science, Department of Anthropology, Laboratory of Morphology and Forensic Anthropology, Kotlářská 2, Brno, 611 37, Czech Republic
| | - Ondřej Klíma
- Brno University of Technology, Faculty of Information Technology, Department of Computer Graphics and Multimedia, Božetěchova 1/2, Brno, 612 66, Czech Republic
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Kumar S, Voracek M, Singh M. Sexual Dimorphism in Digit Ratios Derived from Dorsal Digit Length among Adults and Children. Front Endocrinol (Lausanne) 2017; 8:41. [PMID: 28321205 PMCID: PMC5337486 DOI: 10.3389/fendo.2017.00041] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Accepted: 02/16/2017] [Indexed: 11/13/2022] Open
Abstract
Sexual dimorphism in ventrally measured digit ratios (2D:4D and other) has been related to prenatal sex-hormone levels. In the present series of three studies, we measured all digit lengths (excluding the thumb) on the dorsal, rather than the ventral, side of left and right hands and investigated the sexual dimorphism in digit ratios in three independent samples, two of them comprising adults (Study I, N = 104; Study II, N = 154), and one further, comprising kindergarten children (Study III, N = 64). Results show that men have lower digit-ratio values compared to women in digit ratios that include digit 5 as one of the constituents of the ratio (i.e., the 4D:5D, 3D:5D, and 2D:5D ratios). Boys have lower values compared to girls for the 4D:5D and 3D:5D ratios, and there is a similar trend of sexual dimorphism in the 2D:5D ratio. Thus, based on the evidence from dorsally measured digit ratios, the present findings from three samples are consistent with the idea that early sex-hormonal effects might be stronger for digit ratios involving digit 5, as compared to the classic, and frequently studied, ventrally measured 2D:4D ratio.
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Affiliation(s)
- Sanjay Kumar
- Department of Psychology, D.A.V. College, Muzaffarnagar, India
- *Correspondence: Sanjay Kumar, ; Martin Voracek,
| | - Martin Voracek
- Department of Basic Psychological Research and Research Methods, Faculty of Psychology, University of Vienna, Vienna, Austria
- *Correspondence: Sanjay Kumar, ; Martin Voracek,
| | - Maharaj Singh
- College of Professional Studies, Marquette University, Milwaukee, WI, USA
- Aurora Research Institute, Milwaukee, WI, USA
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Voracek M, Reimer B, Ertl C, Dressler SG. Digit Ratio (2D:4D), Lateral Preferences, and Performance in Fencing. Percept Mot Skills 2016; 103:427-46. [PMID: 17165406 DOI: 10.2466/pms.103.2.427-446] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The second to fourth digit ratio (2D:4D) is a sexually dimorphic trait (men tend to have lower values than women) and a likely biomarker for the organizational (permanent) effects of prenatal androgens on the human brain and body. Prenatal testosterone, as reflected by 2D:4D, has many extragenital effects, including its relevance for the formation of an efficient cardiovascular system. Previous research, reviewed here, has therefore investigated possible associations of 2D:4D with sport performance. Several studies found more masculinized digit ratio patterns (low 2D:4D values or a negative right-minus-left difference in 2D:4D) to be related to high performance in running, soccer, and skiing. The present research tested this hypothesis in a sample of 54 tournament fencers, predominantly from Austria. For men, negative right-left differences in 2D:4D corresponded significantly to better current as well as highest national fencing rankings, independent of training intensity and fencing experience. The mean 2D:4D values of these fencers were significantly lower and the proportion of left-handers was elevated relative to the local general population. For the right hand, the ratio was somewhat lower in male sabre fencers than in male 6pke and foil fencers combined and significantly lower in left-handed compared to right-handed fencers. Although nonsignificant due to low statistical power, effect sizes suggested that crossed versus congruent hand-eye and hand-foot preferences might also be related to fencing performance. The present findings add to the evidence that 2D:4D might be a performance indicator for men across a variety of sports.
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Affiliation(s)
- Martin Voracek
- Department of Basic Psychological Research, School of Psychology, University of Vienna, Liebiggasse 5, Rm 03-42, A-1010 Vienna, Austria.
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Voracek M, Offenmuller D. Digit Ratios (2D:4D and other) and Relative Thumb Length: A Test of Developmental Stability. Percept Mot Skills 2016; 105:143-52. [DOI: 10.2466/pms.105.1.143-152] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Sex and side differences in relative thumb length of children and adolescents have been reported by prior researchers. These findings mirror those reported for the second-to-fourth digit ratio (2D:4D), a likely biomarker for the organizational (permanent) effects of prenatal androgens on the human brain and body. The present study investigated relative thumb length, in particular, its associations with all possible digit ratios (2D:3D, 2D:4D, 2D:5D, 3D:4D, 3D:5D, and 4D:5D), in a sample of young adults (60 men and 64 women). Relative thumb length was less precisely measurable than direct or image-based finger-length measurements, as used in digit ratio research. There were no significant sex or side differences in relative thumb length. Contrary to expectation, thumb size was not positively correlated with any digit ratios. Relative thumb length appears to be developmentally unstable (decreases during childhood and adolescence). Additional findings, such as the magnitude ranking of sex differences in digit ratios and the comparability of direct versus image-based finger-length measurements, are also discussed.
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Frick NA, Hull MJ, Manning JT, Tomkinson GR. Relationships between digit ratio (2D:4D) and basketball performance in Australian men. Am J Hum Biol 2016; 29. [DOI: 10.1002/ajhb.22937] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Revised: 08/18/2016] [Accepted: 10/18/2016] [Indexed: 11/10/2022] Open
Affiliation(s)
- Nathan A. Frick
- Alliance for Research in Exercise, Nutrition, and Activity, Sansom Institute for Health Research and School of Health SciencesUniversity of South AustraliaAdelaide South Australia5001 Australia
| | - Melissa J. Hull
- Alliance for Research in Exercise, Nutrition, and Activity, Sansom Institute for Health Research and School of Health SciencesUniversity of South AustraliaAdelaide South Australia5001 Australia
| | - John T. Manning
- Applied Sports, Technology, Exercise, and Medicine (A‐STEM)Swansea UniversitySwansea United Kingdom
| | - Grant R. Tomkinson
- Alliance for Research in Exercise, Nutrition, and Activity, Sansom Institute for Health Research and School of Health SciencesUniversity of South AustraliaAdelaide South Australia5001 Australia
- Department of Kinesiology and Public Health EducationUniversity of North DakotaGrand Forks North Dakota
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Abstract
SummaryHumans exhibit sex differences in competitiveness, sensation seeking and risk-taking attitude, which are required in sports. These attributes are often linked to prenatal testosterone (PT) exposure. The second-to-fourth digit length ratio (2D:4D) is an indicator of PT exposure. A lower 2D:4D indicates higher PT exposure and vice versa. Males generally have a lower 2D:4D than females. Sensation- and/or thrill-seeking behaviours have also been found to be negatively associated with 2D:4D. Boxing and judo are considered to be high-risk sports. Voluntary participation in judo/boxing in contrast to aerobics can be guided by such behaviours and thus have an association with lower 2D:4D. This cross-sectional study included 167 female students from a military academy in Wrocław, Poland. Of them, 119 had voluntarily chosen aerobic exercise, and 48 opted for judo/boxing. Height, weight and second and fourth digit lengths were measured. Physical fitness was assessed using Eurofit tests. The two groups showed similar physical fitness and body size. However, the judo/boxing group had significantly lower mean 2D:4D values than the aerobics group. It is proposed that voluntary choice of participation in a sport discipline by women could be linked to the ‘organizational’ effect of intrauterine testosterone exposure during prenatal growth.
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Abstract
The second to fourth digit ratio (2D:4D) is claimed to be a biomarker of prenatal sex steroids. This study compared 2D:4D and waist-hip ratio (WHR) in men and women with nose deformity caused by injuries suggesting risky behaviour with those of unaffected controls. This kind of facial trauma was accepted as an indicator of risk-taking behaviour. The study involved 100 patients (50 women aged 30.74±8.09 years and 50 men aged 30.98±10.86 years) who underwent rhinoplasty due to nose trauma in a hospital in Łódź, Poland, in 2015. For comparison purposes, a control sample of 70 women (aged 23.03±3.36 years) and 70 men (aged 22.87±3.46 years) was recruited. In both groups the following measurements were taken: body height, waist and hip circumferences, II and IV digit lengths and body weight. The results showed that women and men who had suffered nose injury had significantly higher values of WHR than controls. The 2D:4D in women with post-traumatic nose deformity was significantly different than the ratio in control women (p<0.0001) and presented the male pattern. It is concluded that in women risky behaviours seem to be associated with prenatal sex hormone influence, while differences in WHR suggest that this tendency is also related to postnatal hormonal factors. Risky behaviours in men should be linked to postnatal hormonal changes rather than to increased prenatal androgen exposure.
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Li G, Huo Y, Sun K, Wang X, Li H, Gao L, Ma B. 2D:4D indicates phimosis risk: A study on digit ratio and early foreskin development. Early Hum Dev 2016; 99:21-5. [PMID: 27390108 DOI: 10.1016/j.earlhumdev.2016.05.013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/19/2016] [Revised: 05/12/2016] [Accepted: 05/24/2016] [Indexed: 11/30/2022]
Abstract
BACKGROUND Many researchers have adopted 2D:4D (second to fourth finger length ratio) as a noninvasive retrospective biomarker for prenatal androgen exposure in recent years. It is thought to be related to diverse traits including behavioral phenotypes, disease susceptibility, and development of urogenital system. OBJECTIVE To examine the relationship between 2D:4D and early foreskin development. METHODS We analyzed the digit ratio and foreskin condition in 176 cases (range 0-6years). The boys were divided into four groups according to their ages: group 1, neonates (below 28days, n=13); group 2, infants (1-12months, n=45); group 3, toddlers (1-2years old, n=42); group 4, preschool children (3-6years old, n=76). We measured the lengths of the second and fourth digits of the left and right hands. The foreskin status was classified into 4 types. Type I (phimosis), type II (partial phimosis), type III (adhesion of prepuce), type IV (normal). RESULTS The phimosis rate was 92.3%, 82.2%, 45.2%, and 38.7% in group 1 to group 4. In contrast, the proportion of normal foreskin increased from 0% in neonates to 13.2% in preschool children. The percentage of higher level of foreskin development shows a downward trend with the increase of digits ratio, and as the age grows, the percentage of normal foreskin cases also increases. CONCLUSIONS These results suggest that a higher R2D:4D (right hand 2D:4D) is a risk factor for phimosis in the early human development. Age is also a significant influence factor of foreskin conditions. Additional research is required to identify pathophysiologic mechanisms and to determine clinical significance.
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Affiliation(s)
- Guanjian Li
- The second Affiliated Hospital of XinJiang Medical University, XinJiang, China
| | - Ying Huo
- School of Public Health, Peking University, Beijing, China
| | - Ke Sun
- The second Affiliated Hospital of XinJiang Medical University, XinJiang, China; XinJiang Medical University, XinJiang, China
| | - Xiaodong Wang
- The second Affiliated Hospital of XinJiang Medical University, XinJiang, China; XinJiang Medical University, XinJiang, China
| | - Hao Li
- The second Affiliated Hospital of XinJiang Medical University, XinJiang, China; XinJiang Medical University, XinJiang, China
| | - Le Gao
- The second Affiliated Hospital of XinJiang Medical University, XinJiang, China
| | - Bin Ma
- The second Affiliated Hospital of XinJiang Medical University, XinJiang, China.
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Vélez MP, Arbuckle TE, Monnier P, Fraser WD. Female digit length ratio (2D:4D) and time-to-pregnancy. Hum Reprod 2016; 31:2128-34. [PMID: 27343270 DOI: 10.1093/humrep/dew164] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Accepted: 06/03/2016] [Indexed: 11/14/2022] Open
Abstract
STUDY QUESTION Is the female 2th- to 4th-finger ratio (2D:4D) associated with fecundity as measured by time-to-pregnancy (TTP)? SUMMARY ANSWER Our study does not support an association between female 2D:4D and TTP. WHAT IS KNOWN ALREADY The 2th- to 4th-finger ratio (2D:4D) has been proposed as a potential indicator of greater androgen exposure during fetal development. Women exposed in utero to unbalanced steroid hormones may have impaired fecundity in the adulthood. Fecundity is often measured by TTP, an epidemiological tool commonly used to assess the impact of environmental factors in human conception. STUDY DESIGN, SIZE, DURATION The Maternal-Infant Research on Environmental Chemicals (MIREC) Study is a pregnancy and birth cohort of 2001 women recruited before 14 weeks of gestation in 10 cities across Canada between 2008 and 2011. The present analysis is part of MIREC-CD Plus, a follow-up study in a subsample of some 800 MIREC mothers and their children from 2012 to 2015. PARTICIPANTS/MATERIALS, SETTING, METHODS TTP and maternal characteristics were collected from questionnaires administered during the first trimester of pregnancy as part of the MIREC study. Digital pictures of the ventral surface of both hands were obtained in the MIREC mothers at the MIREC-CD Plus follow-up study. The 2D:4D was calculated as the ratio of the second and fourth fingers of each hand. The exposure of interest was the 2D:4D of the women categorized by tertiles, or dichotomized as ≥1 (index finger longer than the ring finger) or <1 (ring finger longer than the index finger, implying greater androgen exposure during fetal development). The final sample included 696 mothers. Statistical analyses included discrete-time Cox proportional hazard models, allowing adjustment for potential confounding factors. MAIN RESULTS AND THE ROLE OF CHANCE There was no evidence of diminished/increased fecundability according to the 2D:4D, neither on the right nor on the left hand. In our analysis by tertiles, the smallest 2D:4D (i.e. higher androgen exposure during fetal life) resulted in FORs higher than 1 (i.e. shorter TTP) in both hands, although this was not statistically significant (FOR 1.19 [95% CI 0.93, 1.51] in the right hand and 1.16 [95% CI 0.91, 1.47] in the left hand). In the dichotomous analysis, 2D:4D <1 resulted in FORs higher than 1 (i.e. shorter TTP), but this was also not statistically significant (FOR 1.08 [95% CI 0.88, 1.33] in the right hand and 1.14 [95% CI 0.92, 1.42] in the left hand). Our large sample size resulted in a high statistical power to exclude an association between female 2D:4D and TTP. LIMITATIONS, REASONS FOR CAUTION The MIREC Study is a cohort of pregnant women, and therefore, women with infertility were excluded by design from our study. WIDER IMPLICATIONS OF THE FINDINGS Our data do not provide evidence for an association between female 2D:4D and fecundity as measured by TTP. Whether the female 2D:4D is a marker of in utero androgen exposure and whether it is associated with fecundity have yet to be determined. STUDY FUNDING/COMPETING INTEREST The MIREC Study was funded by Health Canada's Chemicals Management Plan, the Canadian Institute of Health Research (CIHR grant # MOP - 81285), and the Ontario Ministry of the Environment. MIREC-CD Plus was funded by Health Canada's Chemicals Management Plan Research Fund. The 2D:4D component was funded by a research grant from the CIHR-Quebec Training Network in Perinatal Research (QTNPR). M.P. Vélez was supported by a CIHR Fellowship Award, and a QTNPR scholarship. P. Monnier is supported by the Research Institute of the McGill University Health Centre. W.D Fraser is supported by a CIHR Canada Research Chair. There are no conflicts of interest to declare.
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Affiliation(s)
- M P Vélez
- Department of Obstetrics and Gynecology, Kingston General Hospital, Queen's University, Kingston, Canada
| | - T E Arbuckle
- Population Studies Division, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, Canada
| | - P Monnier
- Department of Obstetrics and Gynecology, McGill University Health Centre, Montreal, Canada
| | - W D Fraser
- Sainte-Justine University Hospital Research Centre, University of Montreal, Montreal, Canada Department of Obstetrics and Gynecology, University of Sherbrooke, Sherbrooke, Quebec, Canada
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