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Brink N, Lakhoo DP, Solarin I, Maimela G, von Dadelszen P, Norris S, Chersich MF. Impacts of heat exposure in utero on long-term health and social outcomes: a systematic review. BMC Pregnancy Childbirth 2024; 24:344. [PMID: 38704541 PMCID: PMC11069224 DOI: 10.1186/s12884-024-06512-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Accepted: 04/11/2024] [Indexed: 05/06/2024] Open
Abstract
BACKGROUND Climate change, particularly global warming, is amongst the greatest threats to human health. While short-term effects of heat exposure in pregnancy, such as preterm birth, are well documented, long-term effects have received less attention. This review aims to systematically assess evidence on the long-term impacts on the foetus of heat exposure in utero. METHODS A search was conducted in August 2019 and updated in April 2023 in MEDLINE(PubMed). We included studies on the relationship of environmental heat exposure during pregnancy and any long-term outcomes. Risk of bias was assessed using tools developed by the Joanna-Briggs Institute, and the evidence was appraised using the GRADE approach. Synthesis without Meta-Analysis (SWiM) guidelines were used. RESULTS Eighteen thousand six hundred twenty one records were screened, with 29 studies included across six outcome groups. Studies were mostly conducted in high-income countries (n = 16/25), in cooler climates. All studies were observational, with 17 cohort, 5 case-control and 8 cross-sectional studies. The timeline of the data is from 1913 to 2019, and individuals ranged in age from neonates to adults, and the elderly. Increasing heat exposure during pregnancy was associated with decreased earnings and lower educational attainment (n = 4/6), as well as worsened cardiovascular (n = 3/6), respiratory (n = 3/3), psychiatric (n = 7/12) and anthropometric (n = 2/2) outcomes, possibly culminating in increased overall mortality (n = 2/3). The effect on female infants was greater than on males in 8 of 9 studies differentiating by sex. The quality of evidence was low in respiratory and longevity outcome groups to very low in all others. CONCLUSIONS Increasing heat exposure was associated with a multitude of detrimental outcomes across diverse body systems. The biological pathways involved are yet to be elucidated, but could include epigenetic and developmental perturbations, through interactions with the placenta and inflammation. This highlights the need for further research into the long-term effects of heat exposure, biological pathways, and possible adaptation strategies in studies, particularly in neglected regions. Heat exposure in-utero has the potential to compound existing health and social inequalities. Poor study design of the included studies constrains the conclusions of this review, with heterogenous exposure measures and outcomes rendering comparisons across contexts/studies difficult. TRIAL REGISTRATION PROSPERO CRD 42019140136.
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Affiliation(s)
- Nicholas Brink
- Climate and Health Directorate, Wits RHI, University of the Witwatersrand, Johannesburg, South Africa.
| | - Darshnika P Lakhoo
- Climate and Health Directorate, Wits RHI, University of the Witwatersrand, Johannesburg, South Africa
| | - Ijeoma Solarin
- Climate and Health Directorate, Wits RHI, University of the Witwatersrand, Johannesburg, South Africa
| | - Gloria Maimela
- Climate and Health Directorate, Wits RHI, University of the Witwatersrand, Johannesburg, South Africa
| | | | - Shane Norris
- MRC Developmental Pathways for Health Research Unit, University of the Witwatersrand, Johannesburg, South Africa
| | - Matthew F Chersich
- Climate and Health Directorate, Wits RHI, University of the Witwatersrand, Johannesburg, South Africa
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Puthota J, Alatorre A, Walsh S, Clemente JC, Malaspina D, Spicer J. Prenatal ambient temperature and risk for schizophrenia. Schizophr Res 2022; 247:67-83. [PMID: 34620533 PMCID: PMC8977400 DOI: 10.1016/j.schres.2021.09.020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Revised: 09/20/2021] [Accepted: 09/22/2021] [Indexed: 11/21/2022]
Abstract
OBJECTIVE We conducted a systematic review of the published literature to test the hypothesis that maternal exposure to extremes of ambient temperatures during pregnancy is associated with the risk for psychiatric disorders or congenital malformations in offspring, both of which are indicative of perturbations of fetal neurodevelopment. METHOD This study was conducted in accordance with the recommendations outlined in the Meta-analysis of Observational Studies in Epidemiology (MOOSE) reporting proposal. Electronic databases (Ovid MEDLINE, Ovid Embase, Ovid PsycINFO, Ovid Global Health, Web of Science, and Cochrane Library) were searched. Four independent reviewers selected studies with the following criteria: (1) prenatal maternal ambient temperature exposure; (2) outcome of offspring psychiatric disorder or congenital defects; (3) empirical study; (4) full-length article, no conference presentations or abstracts. RESULTS Twenty-two studies met criteria and one was added from a reference list (n = 23). Of these, schizophrenia (n = 5), anorexia nervosa (n = 3) and congenital cardiovascular malformations (n = 6) studies were the most common. Each of these categories showed some evidence of association with an early pregnancy maternal ambient heat exposure effect, with other evidence for a late pregnancy cold effect. CONCLUSION Some evidence supports a role for early pregnancy maternal exposure to extreme ambient heat in the development of psychiatric disorders, but large-scale, prospective cohort data on individual births is essential. Optimal studies will be conducted in seasonally variable climates, accounting for actual maternal residence over the pregnancy and at parturition, local environmental temperature records, and appropriate covariates, similar to studies identified by this systematic review for congenital malformations.
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Affiliation(s)
| | - Andrea Alatorre
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, United States of America
| | - Samantha Walsh
- Levy Library, Icahn School of Medicine at Mount Sinai, United States of America
| | - Jose C Clemente
- Department of Genetics & Genomic Sciences, Precision Immunology Institute, Icahn School of Medicine at Mount Sinai, United States of America
| | - Dolores Malaspina
- Departments of Psychiatry, Neuroscience, Genetics & Genomics, Icahn School of Medicine at Mount Sinai, United States of America
| | - Julie Spicer
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, United States of America.
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Alvarez-Mon MA, Guillen-Aguinaga S, Pereira-Sanchez V, Onambele L, Al-Rahamneh MJ, Brugos-Larumbe A, Guillen-Grima F, Ortuño F. Being Born in Winter-Spring and at Around the Time of an Influenza Pandemic Are Risk Factors for the Development of Schizophrenia: The Apna Study in Navarre, Spain. J Clin Med 2021; 10:jcm10132859. [PMID: 34203208 PMCID: PMC8267856 DOI: 10.3390/jcm10132859] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 06/23/2021] [Accepted: 06/24/2021] [Indexed: 12/19/2022] Open
Abstract
Background: We analyzed the relationship between the prevalence of schizophrenia and the season of birth and gestation during a period of an influenza pandemic. Methods: Cross-sectional analysis of a prospective population-based cohort of 470,942 adults. We fitted multivariant logistic regression models to determine whether the season of birth and birth in an influenza-pandemic year (1957, 1968, 1977) was associated with schizophrenia. Results: 2077 subjects had been diagnosed with schizophrenia. Logistic regression identified a significantly greater prevalence of schizophrenia in men than in women (OR = 1.516, CI 95% = 1.388–1.665); in those born in the winter or spring than in those born in the summer or autumn (OR = 1.112, CI 95% = 1.020–1.212); and in those born in a period of an influenza pandemic (OR = 1.335, CI 95% = 1.199–1.486). The increase in risk was also significant when each influenza pandemic year was analyzed separately. However, neither month of birth nor season of birth, when each of the four were studied individually, were associated with a statistically significant increase in that risk. Conclusions: The winter–spring period and the influenza pandemics are independent risk factors for developing schizophrenia. This study contradicts many previous studies and thus revitalizes a locked debate in understanding the neurodevelopmental hypothesis of this disorder.
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Affiliation(s)
- Miguel A. Alvarez-Mon
- Department of Psychiatry and Medical Psychology, University of Navarra Clinic, 31008 Pamplona, Spain; (V.P.-S.); (F.O.)
- Department of Medicine and Medical Specialities, University of Alcala, 28805 Alcala de Henares, Spain
- Correspondence: ; Tel.: +34-948255400
| | - Sara Guillen-Aguinaga
- Primary Health Care, Navarra Health Service, 31008 Pamplona, Spain; (S.G.-A.); (A.B.-L.)
- Department of Health Sciences, Public University of Navarra (UPNA), 31008 Pamplona, Spain;
| | - Victor Pereira-Sanchez
- Department of Psychiatry and Medical Psychology, University of Navarra Clinic, 31008 Pamplona, Spain; (V.P.-S.); (F.O.)
- Department of Child and Adolescent Psychiatry, NYU Grossman School of Medicine, New York, NY 10016, USA
| | - Luc Onambele
- École des Sciences de la Santé, Université Catholique d’Afrique Centrale, Yaoundé, Cameroon;
| | - Moad J. Al-Rahamneh
- The Eastern Mediterranean Public Health Network (EMPHNET), Global Health Development (GHD), Amman 11195, Jordan;
| | - Antonio Brugos-Larumbe
- Primary Health Care, Navarra Health Service, 31008 Pamplona, Spain; (S.G.-A.); (A.B.-L.)
- Department of Health Sciences, Public University of Navarra (UPNA), 31008 Pamplona, Spain;
| | - Francisco Guillen-Grima
- Department of Health Sciences, Public University of Navarra (UPNA), 31008 Pamplona, Spain;
- Department of Preventive Medicine, University of Navarra Clinic, 31008 Pamplona, Spain
- Healthcare Research Institute of Navarre (IdiSNA), 31008 Pamplona, Spain
| | - Felipe Ortuño
- Department of Psychiatry and Medical Psychology, University of Navarra Clinic, 31008 Pamplona, Spain; (V.P.-S.); (F.O.)
- Healthcare Research Institute of Navarre (IdiSNA), 31008 Pamplona, Spain
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Korovaitseva GI, Gabaeva MV, Oleichik IV, Golimbet VE. The Effect of INDEL Polymorphism of the Human Leukocyte Antigen G (HLA-G) and the Season of Birth on the Risk of Schizophrenia and Its Clinical Features. RUSS J GENET+ 2021. [DOI: 10.1134/s102279542102006x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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Matsuda K, Park K, Tatsumi H, Kitada R, Yoshiyama M. The Use of Electronic Medical Record Data to Analyze the Association Between Atrial Fibrillation and Birth Month. Online J Public Health Inform 2017; 9:e199. [PMID: 29403578 PMCID: PMC5790432 DOI: 10.5210/ojphi.v9i3.7864] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
OBJECTIVES Cardiovascular disease is a condition of enormous public health concern. Recently, a population study newly revealed associations between cardiovascular diseases and birth month. Here, we investigated the association between atrial fibrillation in cardiovascular disease and birth month. METHODS We retrospectively extracted birth date data from 6,016 patients with atrial fibrillation (3,876 males; 2,140 females) from our electronic medical records. The number of live births in Japan fluctuates seasonally. Therefore, we corrected the number of patients for each birth month based on a Japanese population survey report. Then, a test of the significance of the association between atrial fibrillation and birth month was performed using a chi-square test. In addition, we compared the results of an analysis of patient data with that of simulated data that showed no association with birth month. RESULTS The deviations of birth month were not significant (overall: p = 0.631, males: p = 0.842, females: p = 0.333). The number of female patients born in the first quarter of the year was slightly higher than those born in the other quarters of the year (p = 0.030). However, by comparing the magnitudes of dispersion in the simulated data, it seems that this finding was mere coincidence. CONCLUSION An association between atrial fibrillation and birth month could not be confirmed in our Japanese study. However, this might be due to differences in ethnicity. Further epidemiologic studies on this topic may result in reduction of disease risk in the general population and contribute to public health.
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Affiliation(s)
| | - Keunsik Park
- Department of Medical Informatics, Osaka City
University Hospital, Osaka, Osaka,
Japan
| | - Hiroaki Tatsumi
- Department of Cardiovascular Medicine, Osaka City
University Graduate School of Medicine, Osaka, Osaka,
Japan
| | - Ryoko Kitada
- Department of Cardiovascular Medicine, Osaka City
University Graduate School of Medicine, Osaka, Osaka,
Japan
| | - Minoru Yoshiyama
- Department of Cardiovascular Medicine, Osaka City
University Graduate School of Medicine, Osaka, Osaka,
Japan
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Cheng C, Loh EW, Lin CH, Chan CH, Lan TH. Birth seasonality in schizophrenia: effects of gender and income status. Psychiatry Clin Neurosci 2013; 67:426-33. [PMID: 23992287 DOI: 10.1111/pcn.12076] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/14/2012] [Revised: 12/10/2012] [Accepted: 01/25/2013] [Indexed: 11/30/2022]
Abstract
AIMS The aim of this study was to examine the correlations of birth seasonality in schizophrenia, considering influences of gender and income status. METHODS The sample consisted of 1 000 000 people in the general population randomly selected from the Taiwan National Health Insurance Research Database. Data for the birth-year period 1950-1989 were extracted for analysis (n = 631 911; 306 194 male, 325 717 female). Subjects with schizophrenia (2796 male, 2251 female) were compared with the general population. Subgroups divided by birth-year periods (10-year interval), gender, and income status (low, medium, high) were analyzed using both the Walter and Elwood seasonality and chi-squared tests. RESULTS The winter/spring birth excess in schizophrenia was 5.3% when compared with the general population. There was a statistically significant excess in winter/spring births than summer/autumn births inschizophrenia patients (relative risk [RR], 1.12; 95% confidence interval [CI]: 1.06-1.18). This winter/spring birth excess in schizophrenia was observed only in female subjects (RR, 1.20; 95%CI: 1.10-1.30), not in male subjects (RR, 1.03; 95%CI: 0.98-1.14), in all subgroups of income status, but was most pronounced in the low income subgroup (RR, 1.20, 1.09, 1.13; 95% CI: 1.05-1.37, 1.01-1.17, 1.02-1.25 for low, medium, and high income status, respectively). CONCLUSION A gender difference with female predominance of the effect of birth seasonality in schizophrenia, and a more pronounced effect in low income status were noted.
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Affiliation(s)
- Chin Cheng
- Department of Public Health and Primary Care, School of Clinical Medicine, University of Cambridge, Cambridge, UK
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Hori H, Teraishi T, Sasayama D, Matsuo J, Kawamoto Y, Kinoshita Y, Kunugi H. Relationships between season of birth, schizotypy, temperament, character and neurocognition in a non-clinical population. Psychiatry Res 2012; 195:69-75. [PMID: 21824667 DOI: 10.1016/j.psychres.2011.07.028] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2010] [Revised: 07/13/2011] [Accepted: 07/16/2011] [Indexed: 10/17/2022]
Abstract
While schizophrenia has been associated with a slight excess of winter/early spring birth, it is unclear whether there is such an association in relation to schizotypal personality traits. Season of birth has also been reported to relate to temperament and character personality dimensions and cognitive functioning. Moreover, non-clinical schizotypy has been shown to be associated with mild cognitive impairment, although its precise nature is yet to be elucidated. Here we examined the relationships between season of birth, schizotypal traits, temperament and character, and cognitive function. Four hundred and fifty-one healthy adults completed the Schizotypal Personality Questionnaire (SPQ). The Temperament and Character Inventory (TCI) and a neuropsychological test battery consisting of full versions of the Wechsler Memory Scale-Revised and the Wechsler Adult Intelligence Scale-Revised, and the Wisconsin Card Sorting Test, were also administered to most of the participants. The total SPQ score of those born in winter was significantly higher than that of the remaining participants. Season of birth was not significantly associated with any of the TCI dimensions or cognitive test results. Significant but mild relationships between higher SPQ scores and lower scores on some aspects of IQ were observed. These results support the notion that schizotypy and schizophrenia are neurodevelopmental conditions on the same continuum.
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Affiliation(s)
- Hiroaki Hori
- Department of Mental Disorder Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Kodaira, Tokyo, Japan.
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8
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Mendonça FAS, Machado DR, Lima JAFD, Bortollotti GMF, Grilo RC, Santos GMTD. Correlation between schizophrenia and seasonality of birth in a tropical region. REVISTA BRASILEIRA DE EPIDEMIOLOGIA 2009. [DOI: 10.1590/s1415-790x2009000400004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
OBJECTIVE: To investigate the statistical relationship between season of birth and schizophrenia in 461 patients hospitalized in three psychiatric facilities in the towns of Araras, Itapira, and Espírito Santo do Pinhal, interior of São Paulo State, southeastern Brazil. METHODS: Date and place of birth of the patients were collected and used to determine the season of birth. Results were analyzed by the chi-square test. Data regarding temperature and rainfall between 1952 and 1986, corresponding to the years of birth of the patients studied, were also obtained. RESULTS: The results showed a higher prevalence of births in the winter months (p = 0.0044), a period characterized in this region by a decline in temperature and rainfall. CONCLUSION: These findings indicate a possible influence of seasonality on the pathogenesis of schizophrenia and suggest that the winter in this region, together with other factors, may contribute to the late development of the disease.
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Abstract
Although most Western studies have found a birth excess during winter or early spring among patients with schizophrenia, this has not been found in Japanese samples. The purpose of the present paper was to investigate this finding using a large Japanese sample. Distributions of monthly birth numbers of patients with schizophrenia were compared to those of the general population. Patients were from the governmental data, numbering 88 788. A significant birth excess during winter to early spring was found in male and female subjects with schizophrenia compared to the general population. There is a significant birth excess during winter to early spring for schizophrenia in Japan. The authors consider that the discrepancy between the current study and the previous Japanese studies was caused by small sample size and selection bias in the previous Japanese studies.
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Affiliation(s)
- Yoshio Mino
- Mental Health Section, School of Social Welfare, Osaka Prefecture University, Osaka, Japan.
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10
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Tochigi M, Onai T, Narita K, Hibino H, Rogers M, Umekage T, Kohda K, Otani T, Kanamori R, Kato N, Sasaki T. Seasonality of schizophrenia births in the Japanese population: increased winter births possibly confined to the north area. Schizophr Res 2005; 75:433-8. [PMID: 15885534 DOI: 10.1016/j.schres.2004.08.013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/17/2004] [Revised: 08/21/2004] [Accepted: 08/21/2004] [Indexed: 11/17/2022]
Abstract
A number of North American and European studies have observed a higher proportion of winter births in schizophrenia patients. Thus, seasonal fluctuation of unknown environmental factors may affect brain development in ways that alter susceptibility to schizophrenia. Specification of these factors may help elucidate the etiopathological mechanism of the disease, about which little is certain. A small number of studies have investigated this issue in Asian populations, and the findings are not as consistent as those of Western populations. No remarkable excess of winter births has been observed in Japanese or Korean studies, while some studies have reported a significant decrease of summer births. We further investigated the issue in Japanese patients with schizophrenia (n=3927). No significant excess of winter births was observed, but a decrease in the summer births was found in male subjects. This is largely consistent with previous Japanese studies; however, when the subjects were confined to those born in a colder and higher latitude area of Japan (n=1338), a consistent trend for both a winter increase, and a summer decrease, was found. However, the results did not consistently reach statistical significance, possibly due to the lack of statistical power. Environmental factors that correlate with latitude might play a role in the development of the seasonality of births in schizophrenia. Further studies in a larger sample size are required to test these possibilities.
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Affiliation(s)
- Mamoru Tochigi
- Department of Neuropsychiatry, Graduate School of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033, Japan
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Tustin K, Gross J, Hayne H. Maternal exposure to first-trimester sunshine is associated with increased birth weight in human infants. Dev Psychobiol 2005; 45:221-30. [PMID: 15549686 DOI: 10.1002/dev.20030] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Two alternative hypotheses have been generated to account for seasonal variation in the birth weight of human infants born in industrialized countries. First, it has been hypothesized that low ambient temperature during the second trimester of gestation decreases birth weight. Second, it has been hypothesized that exposure to bright sunshine during the first trimester increases birth weight. We tested these two hypotheses to determine which, if either, accounted for seasonal variation in birth weight of full-term infants. Birth weight data, collected over a 5-year period, were analyzed as a function of peak and trough sunshine and ambient temperature. Although there was no effect of ambient temperature during any trimester on birth weight, infants whose mothers were exposed to peak sunshine during their first trimester were born significantly heavier than infants whose mothers experienced trough levels of sunshine during the same trimester. Furthermore, infants whose mothers were exposed to trough levels of sunshine during their second and third trimesters were born significantly heavier than infants whose mothers were exposed to peak levels of sunshine during the same trimesters. We hypothesize that high levels of sunshine during early gestation may increase the level of insulin-like growth factor (IGF)-1, facilitating prenatal growth.
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Affiliation(s)
- Karen Tustin
- Psychology Department, University of Otago, Dunedin, New Zealand.
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Tochigi M, Marumo K, Hibino H, Otowa T, Kato C, Marui T, Araki T, Otani T, Umekage T, Kato N, Sasaki T. Season of birth effect on personality in a general population. Neurosci Lett 2004; 365:120-3. [PMID: 15245791 DOI: 10.1016/j.neulet.2004.04.064] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2004] [Revised: 04/23/2004] [Accepted: 04/27/2004] [Indexed: 10/26/2022]
Abstract
Seasonality of births in schizophrenia and other mental disorders has been consistently observed. This may be through effects of unknown environmental factors that seasonally fluctuate on the brain development. The effects may affect cognitive function of the brain and behavioral characteristics that might be correlated with the development of personality not only in patients with mental disorders but also in healthy subjects. We, therefore, investigated the effects of season of birth on personality traits in healthy Japanese adults (n = 397). Personality traits were evaluated using the NEO Personality Inventory-Revised (NEO PI-R). A trend for lower Agreeableness in subjects born during winter (December to February) than other subjects was observed (P = 0.036, after correction for the multiple testing, multiple regression analysis adjusting for age and sex). Other major factors of the NEO PI-R, including Neuroticism, Extraversion, Openness and Conscientiousness, were not affected by season of birth. Further studies may be recommended to confirm the results, considering the relatively limited sample size. Evaluation of cognitive functions and behaviors using other measures including event-related potentials and functional MRI may also help the interpretation of the present result.
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Affiliation(s)
- Mamoru Tochigi
- Department of Neuropsychiatry, Graduate School of Medicine, University of Tokyo, Japan
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Abstract
An excess of winter-spring births (and/or a decrease of summer births) has consistently been observed in schizophrenia (SCZ). This observation may provide a significant clue about the causes of the disease if specific factors which cause the phenomenon can be determined. This paper reviews several studies which investigated factors correlated with this observation in SCZ, in an attempt to determine which factors more likely cause the seasonality. Among the candidates of the factors are meteorological variables (such as ambient temperature), several infections, maternal hormones, sperm quality, nutrition and external toxins. A variation of procreation might also have an effect. Among the factors, the most extensively studied are temperature and viral infections. Some of them have appeared promising, but further studies are definitely required. Several challenges, including complicated correlations of the factors and determination of the susceptible period during pregnancy, need to be overcome. Comparisons of the data from areas and cohorts with different patterns of the candidate factors may be helpful. Animal studies may also help investigate the molecular and physiological mechanisms of the phenomenon.
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Affiliation(s)
- Mamoru Tochigi
- Department of Neuropsychiatry, Graduate School of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033, Japan
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Altamura AC, Bassetti R, Bocchio L, Santini A, Mundo E. Season of birth and inflammatory response system in schizophrenia. Prog Neuropsychopharmacol Biol Psychiatry 2003; 27:879-80. [PMID: 12921923 DOI: 10.1016/s0278-5846(03)00122-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Infective agents (e.g., viruses) together with functional alterations of the immune system have been hypothesized to be implicated in the multifactorial pathogenesis of schizophrenia. The viral hypothesis of schizophrenia has been supported by the observation of birth peaks in winter seasons, prenatal exposure to virus epidemics and specific geographic patterns. On the other hand, not all the data published have shown consistent results supporting the immune hypothesis. Thus, it is likely that immune response factors may play a role in the pathogenesis of the disease only in specific subgroups of patients. The aim of the study was to investigate for the presence of differences of IL-6, IL-6R, gp130 and CC16 among four groups of chronic schizophrenic patients categorized according to the season of birth. We hypothesized that patients born in winter and spring would have had increased values of these cytokines. No significant differences were found among the four groups in any of the measures considered. These preliminary results appear to exclude a major role of the season of birth in determining reported interleukins system alterations in chronic schizophrenia.
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Affiliation(s)
- A Carlo Altamura
- Department of Psychiatry, University of Milan, Dipartimento di Scienze Cliniche Luigi Sacco, Via G. B. Grassi, 74, 20157 Milan, Italy.
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Kato C, Petronis A, Okazaki Y, Tochigi M, Umekage T, Sasaki T. Molecular genetic studies of schizophrenia: challenges and insights. Neurosci Res 2002; 43:295-304. [PMID: 12135773 DOI: 10.1016/s0168-0102(02)00064-0] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Schizophrenia (SCZ) is a mental disease that affects approximately 1% of the population with life-long devastating consequences. Based on evidence for a major contribution of genetic factors, a decade of extensive efforts has been dedicated to the search of DNA sequence variations that increase the risk to SCZ. Search for genes in rare multiplex SCZ families with a large number of affected individuals and quasi-Mendelian mode of inheritance using genetic linkage methodology has been one of the favorite strategies in psychiatric genetics. Although several genomic regions were suggested for linkage to SCZ, not a single gene causing or predisposing to SCZ has been identified thus far. Furthermore, it is not clear whether the genes of familial SCZ are also involved in sporadic cases that represent the overwhelming majority of SCZ patients. For sporadic cases, genetic association studies comparing the distribution of allelic frequencies of candidate genes in SCZ patients and controls have been performed but the outcome of such studies has also been quite modest. Several factors such as possible involvement of numerous interactive genes of minor effect, yet unknown environmental effects and diagnostic ambiguities of the disease have made genetic studies in SCZ quite unproductive. In terms of future studies, a genome-wide association search is a promising approach; however, this approach requires genotyping of thousands of genetic markers in large samples. In addition, a detailed analysis of the genes, expression of which changes under the influence of environmental factors, can indicate good candidates for genetic association studies. In this connection, investigations of the epigenetic regulation of genes and not only the DNA sequence variation, may be necessary for complete understanding of the etiopathogenic mechanisms of SCZ.
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Affiliation(s)
- Chieko Kato
- Department of Neuropsychiatry, University of Tokyo, Tokyo, Japan
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