Anogenital distance is associated with genital measures and seminal parameters but not anthropometrics in a large cohort of young adult men

STUDY QUESTION: Is the anogenital distance (AGD) correlated to anthropometric, genital and sperm parameters in young adult men? SUMMARY ANSWER: We observed that reduced AGD is strongly associated with altered semen parameters and reduced testicular volume. WHAT IS KNOWN ALREADY: Abnormalities in the foetal development of the testis have been suggested as causative of common male reproductive disorders, such as cryptorchidism, hypospadias, reduced semen quality and testicular germ cell tumour, collectively defined as 'testicular dysgenesis syndrome'. In human epidemiological studies, alterations in AGD have been frequently associated with clinically relevant outcomes of reproductive health, suggesting AGD as a marker of foetal testicular development. STUDY DESIGN, SIZE, DURATION: This study was performed within the annual screening protocol to evaluate male reproductive health in the high schools of Padua and surroundings (Veneto Region, the North-East of Italy). Here we report the findings of 794 subjects who completed the study protocol between October 2016 and May 2017. PARTICIPANTS/MATERIALS, SETTING, METHODS: We evaluated 794 students aged 18-19 years recording the following parameters: height, weight, BMI, waist circumference, arm span, pubis-to-floor and crown-to-pubis length, penile length and circumference, testicular volumes, semen parameters and AGD (measured from the posterior base of the scrotum to the centre of the anus). MAIN RESULTS AND THE ROLE OF CHANCE: Of the subjects, 49% had an abnormal arm span-height difference (> 3 cm) and 63.4% had an altered ratio of crown-to-pubis/pubis-to-floor length (<= 0.92). The rate of subjects with reduced testicular volume was 23%. Median sperm concentration was 51.0x10(6)/ml and total sperm count was 122.5 x 10(6). AGD showed a direct positive relation with testicular volume and penile length and circumference (R = 0.265, 0.176 and 0.095, respectively, all P < 0.05). No significant relation was observed between AGD and anthropometric parameters. Sperm concentration, total sperm count, progressive motility and normal morphology showed a significant and positive correlation with AGD (R = 0.205, 0.210, 0.216 and 0.117, respectively, all P < 0.05). LIMITATIONS, REASONS FOR CAUTION: Our cohort of young adults is not representative of the general population. Hormonal evaluation was missing. WIDER IMPLICATIONS OF THE FINDINGS: Our findings show that AGD is associated with testicular volumes, penile measures and seminal parameters in young adult men. Because AGD is hormonally determined during foetal life, the reported high incidence of reduced semen quality and reduced testicular volume could be related to a reduced androgenic exposure in utero. AGD could represent a simple and useful method to evaluate testicular and penile development in adult men. STUDY FUNDING/COMPETING INTEREST(S): The authors have no potential conflict of interest to declare. No external funding was obtained for this study.