air pollution and quality of sperm: a meta-analysis

context air pollution is common in all countries and affects reproductive functions in men and women. it particularly impacts sperm parameters in men. this meta-analysis aimed to examine the impact of air pollution on the quality of sperm. conclusions the results of this meta-analysis showed that air pollution reduces sperm motility, but has no impact on the other sperm parameters of spermogram. results the ci for pooled means were as follows: 2.68 ± 0.32 for ejaculation volume (ml), 62.1 ± 15.88 for sperm concentration (million per milliliter), 39.4 ± 5.52 for sperm motility (%), 23.91 ± 13.43 for sperm morphology (%) and 49.53 ± 11.08 for sperm count. evidence acquisition the scientific databases of medline, pubmed, scopus, google scholar, cochrane library, and elsevier were searched to identify relevant articles published between 1978 to 2013. in the first step, 76 articles were selected. these studies were ecological correlation, cohort, retrospective, cross-sectional, and case control ones that were found through electronic and hand search of references about air pollution and male infertility. the outcome measurement was the change in sperm parameters. a total of 11 articles were ultimately included in a meta-analysis to examine the impact of air pollution on sperm parameters. the authors applied meta-analysis sheets from cochrane library, then data extraction, including mean and standard deviation of sperm parameters were calculated and finally their confidence interval (ci) were compared to ci of standard parameters.