The effects of exposure to ozone on sperm quality in Wuhan

Abstract

Objective: To evaluate the effects of exposure to ozone (O(3)) on sperm quality during different stages of spermatogenesis. Methods: All 1 780 subjects attending to the Reproductive Medicine Center in Renmin Hospital of Wuhan University were recruited from April, 4, 2013 to June, 30, 2015. The subjects were living in Wuhan more than 3 months before attending to the program, aged 20 to 40 years. Semen quality (sperm concentration and sperm count) were measured according to standardized protocols. Corresponding daily 8 hours average concentration of O(3), other polluted concentration, average temperature and relative humidity were collected in different time, including lag 0, 10, 70 and 90 d, and lag 0-9 d, lag 10-14 d, lag 70-90 d and lag 0-90 d. After controlling the age, BMI, education level and other confounders, generalized linear Model was used to investigate the association between O(3) and sperm quality during different stages of spermatogenesis. Results: Average daily concentration of O(3) during the study period was (114.20±74.88) μg/m(3) and the mean values of sperm concentration and count were (76.32±50.17) millions/ml and (164.77 ± 133.05) millions/sample, respectively. Exposure to O(3) was associated with decreasing sperm concentration and count. For every 1 μg/m(3) increase of O(3), the decrease of sperm concentration during lag 10, lag 0-9 and lag 10-14 days exposure windows were 0.040 (95%CI: 0.004-0.077) millions/ml, 0.081 (95% CI: 0.003-0.158) millions/ml and 0.059 (95% CI: 0.001-0.116) millions/ml, respectively. And the decrease of sperm count during lag 10, lag 0-9 days exposure windows were 0.105 (95%CI: 0.008-0.202) millions/sample and 0.221 (95% CI: 0.016-0.426) millions/sample. After stratification, in the ozone concentration <P(50) and ≥P(50) groups, and the number of subjects in each exposure windows (lag 0-9, lag 10-14, lag 70-90, lag 0-90 days) were 887 and 893, 890 and 890, 895 and 885, 889 and 891, respectively. Compared with the high ozone concentration group, the effects of low group were more obvious. Furthermore, the effects of low concentration group was the most obvious during lag 10-14 days, for every 1 μg/m(3) increase of O(3), the decrease of sperm concentration was 0.249 (95% CI: 0.028-0.470) millions/ml. After sensitivity analysis, the effects of exposure to ozone on sperm concentration and sperm count remained relatively unchanged. Conclusion: Our study suggested that exposure to O(3) was significantly associated with decreasing semen quality in Wuhan. Moreover, the effects were more obvious during lag 0-9 and lag 10-14 days.