Semen quality and windows of susceptibility: A case study during COVID-19 outbreak in China.

Abstract Background To evaluate the impact of ambient air pollutant exposures on semen quality parameters during COVID-19 outbreak in China, and to identify susceptible windows for associations between air pollution and semen quality. Methods A case study was carried out, including 781 sperm donor candidates (1991 semen samples) collected between November 23, 2019 and July 23, 2020 (a period covering COVID-19 lock-down in China) in University-affiliated Sichuan provincial Human Sperm Bank. Result(s) Our results suggested that sperm motility is susceptible to ambient pollution exposure. Exposure to particulate matters (PM2.5 and PM10), O3 and NO2 during late stage of spermatogenesis appeared to have weak but positive association with semen quality. Exposure to CO late in sperm development appeared to have inverse relationship with sperm movement parameters. Exposure to SO2 appeared to influence semen quality throughout spermatogenesis. Collinearity did not appear to be a major issue in our analysis based on correlationship analysis; we conducted robustness test of the regression results with additional analysis on a subset of our study population to affirm our results. Conclusion(s) Male exposure to different air pollutants have different correlations with semen quality parameters during different exposure windows of spermatogenesis. Findings from current study help to further elucidate the importance of sensitive periods during spermatogenesis and could provide evidence for future intervention in male fertility.