Prenatal Exposure To PCBs Differentially Affects Sperm Head And Tail Morphology Among Adult Male Offspring Of The Child Health And Development Studies

Abstract

Introduction Studies of the association between polychlorinated biphenyls (PCBs) and sperm morphology are contradictory. Two possible reasons are 1) different PCB congeners and congener mixtures may have different effects and 2) the standard measure of percent abnormal sperm combines several outcomes, e.g. abnormal heads and tails. Here we explore the effect of prenatal exposure to PCBs on 3 measures of abnormal sperm morphology. Methods In a follow-up of 196 men from the Child Health and Development Studies cohort, we evaluated associations between prenatal exposure to total PCBs and 15 PCB congeners, both individually and grouped according to chlorination patterns and proposed biological mechanism, and percent abnormal sperm (total, head and tail) at mean age 43. PCBs were measured in stored maternal blood taken immediately postpartum. Sperm morphology was measured in semen collected from adult male offspring and analyzed according to WHO criteria. All analyses adjusted for maternal total lipids, race, income and coffee consumption, and offspring age, smoking, and perceived stress. Results Each ng/mL increase in total PCBs in maternal blood was associated with an increase of 0.92 percent total normal sperm (95% CI: 2.35, -0.51), driven by a reduction in head abnormalities (bhead= -1.30 [-2.31, -0.29] but with contrasting evidence for tail abnormalities (btail=0.49 [-0.38, 1.36]). Among total, grouped and individual PCBs, prenatal exposure was generally associated with fewer head abnormalities and more tail abnormalities and the estimated association was strongest for di ortho substituted PCBs Conclusions Prenatal PCB exposure may have opposite effects on sperm head and tail morphology, warranting further research into the influence of PCBs on the development of fetal Sertoli cells. Prenatal PCB exposure may create an unfavorable environment for production or survival of sperm with head abnormalties. The clinical consequences of this finding are uncertain.