Comparability and reproducibility of adult male anogenital distance measurements for two different methods

Maternal phthalate exposure during pregnancy and testis function of young adult sons

BACKGROUND

Phthalate exposure during fetal life may disrupt testicular development. Congruent with this, studies have found shorter anogenital distance, reduced penile size and altered hormone levels in infant boys whose mothers were exposed to higher levels of some phthalates during pregnancy. Few studies have explored if such adverse effects persist in adulthood. Thus, we aimed to explore if there is an association between fetal phthalate exposure and markers of testicular function in young adult men.

METHODS

In a longitudinal mother-child cohort from Copenhagen, Denmark, we examined 100 young men whose mothers during pregnancy had serum drawn and analyzed for 34 phthalate metabolites. Examinations of the young men took place at 18-20 years of age and included measurements of adult markers of testicular function (reproductive hormones, penile size, anogenital distance (AGD), testis volume, semen quality) and growth factors. Associations between maternal serum concentrations of phthalate metabolites and reproductive measures in the young men were tested using multiple linear regression.

RESULTS

Most consistently, higher maternal phthalate exposure was associated with higher luteinizing hormone (LH) but unchanged testosterone in adult sons. Congruently, higher maternal exposure was associated with lower total and free testosterone/LH ratios in adult sons. For example, twice as high maternal MiNP was associated with a 7.9 % (95 % CI 1.6-13.8) lower free testosterone/LH ratio. There was no consistent pattern of associations between the different phthalate metabolites and other reproductive hormones, clinical outcomes, or semen quality. None of the tested associations was significant after multiplicity adjustment.

CONCLUSIONS

In this exploratory study, higher maternal exposure to some phthalates was associated with impaired testicular Leydig cell function evidenced by a lower total and free testosterone/LH ratio in adult sons. This unique 18-20-year follow-up study raises concern and suggests that exposure of pregnant women to phthalates may have long-term effects on adult reproductive health in male offspring.

Anogenital distance, male factor infertility and time to pregnancy

BACKGROUND

Anogenital distance (AGD), the distance between the anus and genitals, is in rodents a well-established marker of early androgen action and has been suggested to be so in humans as well. Thus, a link between human AGD and semen quality and potentially fecundity may exist.

OBJECTIVE

The aim of this study was to assess the association between AGD and male factor infertility and among proven fertile men also time to pregnancy (TTP).

MATERIAL AND METHODS

All included men were recruited from and examined at Copenhagen University Hospital, Denmark (N=388). Men with impaired semen quality were included from infertile couples (N=128), and men with naturally conceived pregnant partners were invited to participate when their partners had their routine second trimester examination (N=260). All men underwent a physical examination, completed a questionnaire (including TTP for the fertile men), delivered a semen sample and had a blood sample drawn. The primary exposure was AGD_AS measured from the centre of the anus to the posterior base of the scrotum. Associations between AGD and fertility status as well as between AGD and TTP among the fertile men were calculated using multiple logistic regression adjusted for covariates.

RESULTS

AGD did not show a statistically significant association with fertility status. In adjusted logistic regression models, the odds of infertility per 1 cm increase in AGD_AS was 1.02 (95% CI: 0.88; 1.19). Amongst fertile men, a 1 cm increase in AGD_AS was associated with an 8% non-statistically significantly reduced odds of having a longer (>3months) TTP (adjusted OR= 0.92, 95%CI: 0.76-1.11).

CONCLUSION

Our study showed that the clinical application of AGD as a predictor of fertility and fecundity seems to be limited as no associations were observed between AGD and fertility status, nor was the decreased risk of experiencing a longer TTP with longer AGD_AS statistically significant. This article is protected by copyright. All rights reserved.

The use of anogenital distance as a non-invasive predictor of seminal quality in captive squirrel monkey (Saimiri collinsi Osgood 1961)

BACKGROUND

Anogenital distance is considered a non-invasive measure to assess the development and functionality of sexual organs in different animal species. Hence, this measurement could potentially be used during the selection of non-human primates for reproductive biotechnology programs. The aim of this study was to assess the correlation between anogenital distance and reproductive parameters in captive Saimiri collinsi.

METHODS

Eight mature S. collinsi males were evaluated. Body weight, reproductive hormone levels, testicular volume, and seminal parameters were determined, and their relationship with anogenital distance measurements was assessed.

RESULTS

Anogenital distance was correlated with seminal volume, sperm motility, vigor, and plasma membrane integrity, but not with body weight, reproductive hormones, and testicular volume.

CONCLUSION

The determination of anogenital distance is a non-invasive method to predict seminal quality. This procedure has the advantage of providing andrologic information without a negative impact on animal welfare.

Testicular cancer survivors have shorter anogenital distance that is not increased by 1 year of testosterone replacement therapy

STUDY QUESTION

Is anogenital distance (AGD) shorter in testicular cancer (TC) survivors than in men from the general population, and is AGD affected by testosterone replacement therapy in adulthood?

SUMMARY ANSWER

AGD, measured as distance from anus to scrotum (AGDas), is shorter in TC survivors and does not change as a result of testosterone replacement therapy.

WHAT IS KNOWN ALREADY

Animal studies have shown that AGD is a postnatal 'read-out' of foetal androgen action, and short AGD in male offspring is considered a sign of feminization caused by in utero disruption of the reproductive system. Likewise, measurement of AGD in human studies has suggested AGD to be part of the testicular dysgenesis syndrome hypothesis, which proposes that male reproductive disorders, such as hypospadias, cryptorchidism, some cases of impaired semen quality and TC, all share a common foetal origin.

STUDY DESIGN, SIZE, DURATION

The aim was to assess AGD in men with a history of TC and controls, and furthermore to examine AGD during testosterone replacement therapy in adulthood. Study participants were TC survivors with a mild Leydig cell insufficiency who participated in a randomized double-blind study of testosterone replacement therapy versus placebo for 52 weeks (N = 69). Men from the general population were prospectively included from a study on testicular function as controls (N = 67).

PARTICIPANTS/MATERIALS, SETTING, METHODS

We measured two variants of AGD; as our primary outcome the anoscrotal distance (AGDas) measured from the centre of the anus to the posterior base of the scrotum, and secondarily the anopenile distance (AGDap) measured from the anus to the cephalad insertion of the penis. Using multiple regression analysis, the mean difference in AGD between TC survivors and men from the general population was assessed, adjusted for height, BMI and examiner. Next, AGD was measured before and after 52 weeks of treatment with testosterone or placebo, and with covariance analysis differences between the two groups at follow-up was assessed after adjustment for baseline AGD, examiner, BMI and change in BMI during treatment.

MAIN RESULTS AND THE ROLE OF CHANCE

TC survivors had a shorter AGDas (-0.84 cm, 95% CI: -1.31; -0.37) compared to men from the general population, and AGDas did not differ between the testosterone and placebo treated group at follow-up (0.11 cm, 95% CI: -0.22; 0.44). In contrast, AGDap was not shorter in TC survivors after adjustment (0.05 cm, 95% CI: -0.30; 0.39), and was 0.48 cm longer (95% CI: 0.13; 0.82) at follow-up in the testosterone treated compared to the placebo-treated group.

LIMITATIONS, REASONS FOR CAUTION

A limitation of the study is that the number of included men was limited, and results need confirmation in a larger study. Furthermore, TC survivors were significantly older than controls. For the comparison of AGD in TC survivors and controls, it was not possible to conduct the examinations with the examiner being blinded to which group he was examining, and it cannot be excluded that this can cause a bias.

WIDER IMPLICATIONS OF THE FINDINGS

The shorter AGDas in TC survivors compared to controls, which did not change upon adult testosterone replacement therapy, supports the hypothesis that reduced AGD is part of the testicular dysgenesis syndrome and may be a marker of disrupted foetal testicular development. By contrast, AGDap was not shorter in TC survivors and might be modestly sensitive to adult testosterone treatment, and thus inferior to AGDas as a constant postnatal marker of the foetal androgen environment.

STUDY FUNDING/COMPETING INTEREST(S)

Expenses were paid by the Department of Oncology, Copenhagen University Hospital, Rigshospitalet. Kiowa Kirin International covered expenses for Tostran and placebo. The Danish Cancer Society, The Danish Cancer Research Foundation, the Preben & Anna Simonsen Foundation, and Rigshospitalet have supported the study. L.P. was financed by the Research Fund of the Capital Region of Denmark. The authors have no competing interests.

TRIAL REGISTRATION NUMBER

Part of the study is based on men participating in a randomized controlled trial registered at ClinicalTrials.gov, NCT02991209, 25 November 2016.

Shorter anogenital distance is observed in patients with testicular microlithiasis using magnetic resonance imaging

OBJECTIVE

To investigate the anogenital distance in patients with and without testicular microlithiasis (TML).

METHODS

A total of 101 patients underwent a conventional standard clinical B-mode scrotal ultrasonography and scrotal MRI. The patients were divided into two groups: patients with TML and non-TML. The latter served as control group. The anogenital distance was measured by a straight line from center of the anus to the posterior base of scrotum using MRI.

RESULTS

In the TML group, mean AGD was 5.4 (± 1.07) cm (range 29-79 mm), and in non-TML 5.9 (± 1.03) cm (range 35-85 mm) (p = 0.04).

CONCLUSION

MRI is a useful tool to measure the AGD. It is easy to perform without any discomfort to patients. We found AGD to be lower in patients with TML.

Association between pre/perinatal exposure to POPs and children's anogenital distance at age 4 years: A study from the INMA-Asturias cohort

BACKGROUND

Prenatal exposure to endocrine-disrupting chemicals may impair genital development and alter reproductive tract anatomy. Anogenital distance (AGD) is a useful biomarker of exposure to chemicals that act as endocrine disruptors. We evaluated associations between prenatal and perinatal exposure to several persistent organic pollutants (POPs) and AGD in 4-year-old children.

METHODS

Data were drawn from the INMA-Asturias cohort. Pediatricians measured the anofourchetal distance in female children and anoscrotal distance in male children. The anogenital index (AGI) was defined as the AGD divided by the child's weight at age of examination. We measured the levels of two hexachlorocyclohexane isomers, hexachlorobenzene, dichlorodiphenyltrichloroethane (DDT) and its metabolites, six polychlorinated biphenyl (PCB) congeners, and six polybrominated diphenyl ether (PBDE) congeners in maternal serum at 12 gestational weeks (n = 155) and in cord blood serum (n = 229). Anthropometric and parental sociodemographic variables were collected via face-to-face interviews. Linear regression models were used to evaluate the relationship between exposure to POPs and AGI, adjusted for confounders and stratified by sex.

RESULTS

In male children, we found inverse associations between AGI and maternal concentrations of PCB-138 (ß = -0.041, 95% confidence interval [CI]: -0.074, -0.008, second tertile), PCB-153 (ß = -0.052, 95% CI: -0.085, -0.020, second tertile), PCB-180 ß = -0.065, 95% CI: -0.096, -0.035, second tertile; ß = -0.042, 95% CI: -0.073, -0.011, third tertile), PBDE-209 (ß = -0.031, 95% CI: -0.058, -0.006), cord serum concentrations of PCB-153 (ß = -0.029, 95% CI: -0.059, -0.000, second tertile; ß = -0.047, 95% CI: -0.085, -0.008, third tertile), and PCB-180 (ß = -0.041, 95% CI: -0.078, -0.005, third tertile). In female children, AGI was positively associated with maternal serum concentrations of PCB-101 (ß = 0.039, 95% CI: 0.002, 0.076, second tertile), and higher cord serum levels of 4,4'-DDT (ß = 0.032, 95% CI: 0.003, 0.061, third tertile) and 4,4'-DDE (ß = 0.040, 95% CI: 0.011, 0.069, third tertile).

CONCLUSIONS

Our findings provide evidence of associations between specific POPs and AGI in boys and girls aged 4 years, and suggest that pre/perinatal exposure to POPs has a feminizing effect in males and a masculinizing effect in females.

[Study of anogenital distance as a diagnostic tool for prostate cancer]

INTRODUCTION AND OBJECTIVE

The distance from the genitals to the anus (anogenital distance [AGD]) reflects androgen concentration during prenatal development in mammals. At the present time, there is only one study suggesting the relationship between AGD and risk of prostate cancer (CaP). The goal of this study was to assess the performance and clinical utility of AGD, as a biomarker of prenatal androgenic milieu, and risk of CaP in a larger population, in CaP diagnosis.

MATERIAL AND METHODS

A case-control study was conducted on 260 men seen in a hospital outpatient clinic where underwent a physical and andrological examination and completed a brief questionnaire. CaP patients were confirmed by biopsy of the tumor. Controls were men without CaP seen in the urology outpatient clinic for routine examinations. Two variants of AGD (from the anus to the posterior base of the scrotum [AGD_AS] and to the cephalad insertion of the penis [AGD_AP]) were measured. Parametric and non-parametric tests and receiver operating characteristic (COR) analyses were used to determine relationships between AGD and presence of CaP.

RESULTS

The highest area under the curve (0.69; 95% CI 0.60 to 0.78 and 0.69; 95% CI 0.61 to 0.77) was obtained for the Gleason=7 subgroup with the AGD_AS and AGD_AP measurement, with a sensitivity and specificity of 83% and 55%, and 91% and 41%, the predictive positive value of 39% and 35% and negative value of 90% and 93% respectively.

CONCLUSION

AGD may be a useful clinical tool for the CaP diagnosis.

Anogenital distance and reproductive outcomes in 9- to 11-year-old boys: the INMA-Granada cohort study

BACKGROUND

Studies examining the association of anogenital distance (AGD), a biomarker of prenatal androgen exposure, with sexual development in children are lacking.

OBJECTIVE

To assess the association between AGD measures and reproductive outcomes, including puberty onset, testicular volume, reproductive hormone levels, and urogenital malformations in boys aged 9-11 years.

MATERIALS AND METHODS

A cross-sectional study was conducted among children belonging to the Spanish Environment and Childhood (INMA) Project, a population-based birth cohort study. The present sample included 279 boys for whom data were available on AGD, pubertal stage, testicular volume, and relevant covariates. Out of the boys with AGD data, 187 provided a blood sample for hormone analysis. AGD was measured from the center of the anus to the base of the scrotum. Pubertal development was assessed according to Tanner stage of genital development (G1-G5), and testicular volume was measured with an orchidometer.

RESULTS

After adjusting for potential confounders, logistic regression analysis showed that AGD was positively associated with testicular volume but not with Tanner stage (>G1 vs. G1), serum hormone levels, or undescended testis. Regardless of their age, body mass index, and Tanner stage (G1 or >G1), boys with longer AGD showed increased odds of a testicular volume >3 mL (OR = 1.06, 95%CI = 1.00-1.19 per 10% increment in AGD; and OR = 3.14, 95%CI = 0.99-9.94 for AGD >42 mm vs. <33 mm).

DISCUSSION

Longer AGD was associated with testicular growth, an indicator of gonadarche, but not with other reproductive outcomes.

CONCLUSIONS

Although AGD was positively associated with testicular volume, it remains unclear whether AGD predicts testis size at puberty or is related to puberty onset.

Assessing the impact of in-utero exposures: potential effects of paracetamol on male reproductive development

Human male reproductive disorders (cryptorchidism, hypospadias, testicular cancer and low sperm counts) are common and some may be increasing in incidence worldwide. These associated disorders can arise from subnormal testosterone production during fetal life. This has resulted in a focus on in-utero environmental influences that may result in reproductive effects on the offspring in later life. Over recent years, there has been a dramatic increase in the scientific literature describing associations between in-utero environmental exposures (eg, industrial chemicals and pharmaceuticals) and subsequent reproductive outcomes in male offspring. This includes studies investigating a potential role for in-utero analgesic exposure(s) on the fetal testis; however, providing definitive evidence of such effects presents numerous challenges. In this review, we describe an approach to assessing the potential clinical relevance of in-utero (and postnatal) environmental exposures on subsequent male reproductive function using exposure to the analgesic paracetamol as an example.

Anogenital distance and variability in semen parameters

The purpose of this study was to analyze whether the anogenital distance (AGD) was associated with variability in semen parameters. Semen parameters analyzed following the WHO guidelines and sperm DNA fragmentation were evaluated in 160 semen samples obtained over a period of a year from 16 healthy male volunteers. Two types of AGD measurements from the anus to the rear base of the scrotum (AGD_AS) and to the cephalic insertion of the penis (AGD_AP) were taken in each individual. The association between AGDs and semen parameters were studied using three statistical tools: a) general coefficient of variation (CV) and intra-individual coefficient of variation (CV_i), b) general linear models for repeated measures, and c) mixed model fixed effects panel data. Men with shortened AGD_AP have significantly greater intra-individual variability in sperm concentration, total sperm count, and normal sperm morphology. Conversely, greater total sperm motility was observed in men with long AGD_AS. Shortened AGD_AS was associated with less intra-individual variability of total sperm motility (progressive and non-progressive). AGD measurements were associated with the variability in semen parameters. AGD may be useful to determine intra-individual variability in semen parameters.

ABBREVIATIONS

AGD: anogenital distance; AGD_AP: anogenital distance from the anus to the cephalic insertion of the penis; AGD_AS: anogenital distance from the anus to the rear base of the scrotum; AIC: Akaike information criteria; BMI: body mass index; CV: general coefficient of variation; CV_i: intra-individual coefficient of variation; GLM: generalized linear model; PR+NP: total sperm motility.