Effects of environmental pyrethroids exposure on semen quality in reproductive-age men in Shanghai, China.

Background: Animal experiments have revealed that pyrethroids (PYRs) exposure could affect semen quality, however evidence on humans being is limited and controversial.

Objective: To explore the potential effects of environmental PYRs exposure on semen quality in reproductive age men.

Methods: We conducted a cross-sectional study of 346 men who planned to conceive and addressed to hospital for preconception examination. PYRs exposure was assessed by analyzing PYRs urinary metabolites [3-phenoxybenzoic acid (3PBA), trans- and cis-3-(2,2-Dichlorovinyl) -2,2-dimethylcy clopropane carboxylic acid (TDCCA and CDCCA)] levels using gas chromatography-mass spectrometry. Semen quality was assessed by a computer-aided semen analyzer.

Results: For a detection rate of 99.7%, 76.6%, and 22.0%, the median levels (μg/g creatinine) of PYRs metabolites were 0.46 for 3PBA, 0.38 for TDCCA and under detection limit for CDCCA. Linear regression models found negative associations between 3PBA and sperm morphology (β = -2.12, 95% CI: -4.02 to -0.22) as well as between TDCCA and log-transformed total sperm count (β = -0.09, 95% CI: -0.16 to -0.01). In logistic regression models, men with the highest quartile of 3PBA had higher risk of poor semen quality (having below-reference semen parameter, OR = 2.40, 95% CI: 1.26 to 4.54; having below-reference sperms morphology, OR = 3.08, 95% CI: 1.10 to 8.60) compared to men in the lowest quartile.

Conclusions: Our study suggests that environmental PYRs exposure might adversely affect semen parameters of reproductive age men in Shanghai, China. Further studies are needed to confirm our findings and demonstrate a causal relationship between PYRs exposure and semen quality.