Effects of particulate matter exposure on semen quality: A retrospective cohort study

Background: Particulate matter (PM) exposure is closely associated with male infertility. Even though an association between poor semen quality and PM exposure has been widely accepted, which and when the semen parameter could be affected are still controversial. The purpose of this study is to estimate the effects of PM exposure on semen quality in Huai'an, China. Objectives and methods: The study included 1955 men with 2073 semen samples between 2015 and 2017 with moderate to high exposure to air pollution in Huai'an, China. Three multivariable linear regression models were used to conduct exposure-response analyses for PM exposure and semen quality and to estimate the influence during different exposure periods by every 15 days period before ejaculation in all participants group and normal semen quality participants group. Results: The average age of the observations was 28.9 +/- 5.4 old years and the average abstinence period was 4.2 +/- 1.5 days. The results showed high correlations between both PM2.5 and PM10 exposures throughout entire spermatogenesis and the declines of sperm count (beta: -0.93, p < 2 x 10(-16) and beta: -1.00, p < 2 x 10(-16)), and sperm concentration (beta: -1.00, p < 2 x 10(-16) and beta: -1.06, p < 2 x 10(-16)), and PM10 exposure decreased sperm total motility (beta: -0.60, p = 2.56 x 10(-7)), but not sperm progressive motility. Furthermore, PM2.5 exposure decreased sperm count and concentration during 15-75 lag days, and PM10 exposure showed significant association with sperm count and concentration during 0-75 lag days. PM2.5 and PM10 exposures during 45-59 lag days were both inversely associated with sperm total motility (all p value < 0.05). Conclusion: The present study revealed that ambient PM exposure throughout spermatogenesis during a long period, especially at early and middle stage were adversely associated with semen quality, sperm count and sperm concentration in particular.