Effect Of Exposure To Chlorination Disinfection By-products In Drinking Water On Semen Quality: A Cross- Sectional Study

Objective: Toxicological studies indicated an association between exposure to chlorinated disinfection by-products (CDBPs) and impaired male reproductive health in animals while epidemiological evidences in human are still needed. Till now, relevant epidemiological studies are still limited and no consistent conclusion has been drawn. We conducted a cross-sectional study to investigate the effect of exposure to CDBPs on human male reproductive health.Methods: We recruited 418 male partners in sub-fertile couples seeking infertility diagnosis from Wuhan Tongji Hospital. Their semen samples were collected and analyzed for semen quality. Exposures to CDBPs were estimated by their urinary creatinine (Cr) adjusted trichloroacetic (TCAA) concentrations. We used non-conditional logistic regression to assess the relationship between exposure to CDBPs and semen quality controlling for potential confounders.Results: TCAA concentrations in the 418 urine samples ranged < limit of detection (LOD) ~ 95.1 ng/ml. The mean, median, and geometric mean were 7.9, 7.4, and 6.5ng/ml, respectively. The Cr-adjusted TCAA levels ranged 0.3 ~ 147.5μg/g Cr. The mean, median, and geometric mean were 9.2, 5.1, and 5.6μg/g Cr, respectively.Cr-adjusted TCAA concentrations were categorized into quartiles. After adjusting for age, abstinence time and smoking status, the odds ratios (95% CI) for below reference sperm concentration of each exposure quartile were 1.0, 1.8 (0.6~5.3), 1.6 (0.5~4.9) and 1.5 (0.5~4.6). When exposure levels were dichotomized with the cut-point of the 25% percentile, the adjusted odds ratios (95% CI) for each group were 1.0 and 1.6 (0.6~4.2). The adjusted odds ratios (95% CI) for below reference sperm motility of each exposure quartile were 1.0, 1.5 (0.8~2.7), 1.5 (0.8~2.7) and 1.5 (0.8~2.7). The adjusted odds ratios (95% CI) for sperm motility of each dichotomized group were 1.0 and 1.5 (0.9~2.4) Conclusion: No significant association of decreased sperm concentration with elevated urinary TCAA levels was found in this study. The present study provided suggestive but inconclusive evidence for the relationship of sperm motility with elevated urinary TCAA levels. The effect of exposure to CDBPs on human male reproductive health still warrants further investigations with larger sample size and better study design.