Abstract
Objective: To understand how chronic exposure to industrial air pollution is associated with male fertility through semen parameters.
Design: Retrospective cohort study.
Subjects: Men in the Subfertility, Health and Assisted Reproduction cohort who underwent a semen analysis 2005-2017 with ≥1 measured semen parameter (N=21,563).
Exposure: Residential histories for each man were constructed using locations from administrative records linked through the Utah Population Database. Industrial facilities with air emissions of nine endocrine disrupting compound chemical classes were identified from the Environmental Protection Agency Risk-Screening Environmental Indicators microdata. Chemical levels were linked with residential histories for the 5 years prior to each semen analysis.
Results: Following adjustment for demographic covariates, several chemical classes were associated with azoospermia and decreased total motility and volume. For exposure in the 4th relative to 1st quartile, significant associations were observed for acrylonitrile (βtotal motility=-0.87pp), aromatic hydrocarbons (ORazoospermia=1.53; βvolume=-0.14mL), dioxins (odds ratio [OR]azoospermia=1.31; βvolume=-0.09mL; βtotal motility=-2.65pp), heavy metals (βtotal motility=-2.78pp), organic solvents (ORazoospermia=1.75; βvolume=-0.10mL), organochlorines (ORazoospermia=2.09; βvolume=-0.12mL), phthalates (ORazoospermia=1.44; βvolume=-0.09mL; βtotal motility=-1.21pp), and silver particles (ORazoospermia=1.64; βvolume=-0.11mL). All semen parameters significantly decreased with increasing socioeconomic disadvantage. Men who lived in the most disadvantaged areas had concentration, volume, and total motility 6.70M/mL, 0.13mL, and 1.79pp lower, respectively. Count, motile count, and total progressive motile count all decreased by 30-34M.
Conclusion: Several significant associations between chronic low-level environmental exposure to endocrine disrupting compound air pollution from industrial sources and semen parameters were observed. The strongest associations were seen for increased odds of azoospermia and declines in total motility and volume. More research is needed to further explore additional social and exposure factors as well as to expand on the risk posed to male reproductive health by the studied chemicals.
