Associations between low-dose triclosan exposure and semen quality in a Chinese population

Background: The antimicrobial agent triclosan (TCS) has attracted much attention worldwide because of its pervasive existence in the human body and environment. TCS exposure has been reported to be associated with decreased male reproductive function. However, few studies have investigated these associations in humans. Objective: To examine the relationship between TCS in urine and male semen quality. Methods: A total of 406 men from a reproductive clinic were enrolled in this study. Urinary TCS concentrations were determined by ultra-high performance liquid chromatography-electrospray ionization tandem mass spectrometry. Sixteen semen parameters were assessed according to the guidelines of World Health Organization (WHO), including parameters for volume, count, motility, and motion. We used multivariate linear regression models and restricted cubic splines to estimate the linear and non-linear associations between TCS exposure and semen parameters, respectively. Logistical regression models were further applied to explore the associations with abnormal semen quality. Results: TCS was detected in 74.6% of urine specimens. The monotonous trend of TCS tertiles and continuous TCS levels with all semen quality parameters were not observed in multivariate linear regression models (p > 0.05). However, compared with those in the lowest tertile, subjects in the second tertile showed significantly higher linearity and wobble (p < 0.05), indicating potential effects on sperm motion. In the models using restricted cubic splines with 3-5 knots, there were no significant non-linear associations between TCS exposure and any semen quality parameter. In addition, TCS tertiles were not associated with the risk of abnormal semen quality (i. e., count and motility) in the logistical regression models. Conclusion: Our results revealed that low-level TCS exposure may have limited (none or modest) effects on male semen quality, potentially inducing some fluctuations. Further mechanistic studies on low levels of exposure are needed.