Exposure to polychlorinated biphenyls (PCBs) and male reproduction.

Polychlorinated biphenyls (PCBs) are a class of persistent organic pollutants that were widely used in the mid-20th century. Though their production and use was banned by most countries several decades ago, the general population continues to be exposed due to the persistence and bioaccumulation of PCBs. A number of human epidemiological studies have assessed the relationship between environmental PCB exposure and markers of male reproductive health, namely semen quality parameters (sperm concentration, motility, and morphology), sperm DNA integrity (DNA damage or chromatin fragmentation), and circulating reproductive hormone levels. Despite a wide range of study designs and locations, measurement methods, and PCB exposure levels, reports of inverse associations between PCBs and sperm motility have been consistent which may suggest a lack of exposure threshold for a PCB-related effect on sperm motility. Several studies have also reported inverse associations between PCBs and circulating testosterone levels in men, though the specific form of testosterone (i.e. total, bound, or free testosterone) associated with exposure has not been fully consistent between studies. In conclusion, although PCBs are no longer used and can be considered a legacy chemical, concerns regarding altered male fertility in relation to PCBs remain due to the existing human data demonstrating inverse associations with markers of male reproductive function coupled with recent evidence for continued population exposure.