Atopic Dermatitis in Childhood and Biomarkers of Male Reproductive Health: A Danish National Birth Cohort Study

BackgroundAtopic dermatitis (AD) may be associated with male reproductive health. However, epidemiological studies are yet to explore this hypothesis.ObjectivesTo investigate whether AD in childhood is associated with poorer reproductive health in young men from the general population.MethodsThis study is based on the Danish National Birth Cohort (DNBC) and its sub-cohort, the Fetal Programming of Semen Quality cohort (FEPOS), which consists of young men born between 1998 and 2000 and whose mothers were included in the DNBC. In total, 5697 young men were invited during the recruitment period from 2017 to 2019, where 1058 were enroled and completed a comprehensive questionnaire regarding health and lifestyle, provided semen and blood samples and self-measured their testicular volume. Information on maternal-reported doctor-diagnosed AD was obtained from the DNBC during childhood. The associations of semen characteristics, testicular volume and reproductive hormone levels with the occurrence of AD were analyzed using negative binomial and linear regression models.ResultsIn total, 220 (21%) young men had childhood AD. Men with childhood AD had slightly higher sperm concentration compared to those without (17%, 95% confidence intervals (CI): 3% to 33%), and lower FSH (-9%, 95% CI: -17% to 0%) and LH (-8%, 95% CI: -14% to -1%). Testosterone and estradiol levels and the remaining reproductive health outcomes were comparable between men with and without childhood AD.ConclusionsThis study indicates that childhood AD might not have a clinically significant negative association with semen quality or reproductive hormone levels in young adulthood.