Environmental exposure to legacy poly/perfluoroalkyl substances, emerging alternatives and isomers and semen quality in men: A mixture analysis
By Kai Luo, Wei Huang, Qianlong Zhang, Xiaotu Liu, Min Nian, Mengdan Wei, Yuqing Wang, Da Chen, Xiangfeng Chen, and Jun Zhang
Sci Total Environ
April 19, 2022
DOI: 10.1016/j.scitotenv.2022.155158
Background/objectives
Multiple studies have examined the relationship between PFAS and semen quality, but none has explored the associations of PFAS mixture that includes emerging alternatives and branched isomers.
Methods
22 PFAS, including 10 linear legacy PFAS, 7 branched isomers, 3 short chain alternatives and 2 components of F53B [e.g., 6:2 chlorinated polyfluorinated ether sulfonate (Cl-PFESA)] were quantified in blood plasma among 740 healthy men. Five semen quality parameters (i.e., volume, count, concentration, total motility and progressive rate) were assessed. Multiple linear regression and three multiple pollutant models (i.e., adaptive elastic net regression, quantile based g-computation, and XGBoost method) were used to assess the associations of individual PFAS, PFAS mixture and the potential interactive effects among congeners.
Results
After adjusting for selected confounders, perfluorobutane sulfonate (PFBS) and perfluorohexane sulfonate (PFHxS) presented significant and negative associations with sperm count [β = -0.09 (95%CI: -0.14, -0.03) for PFBS, and -0.16 (95%CI: -0.25, -0.07) for PFHxS] and sperm concentration [-0.04 (95%CI: -0.08, -0.001) for PFBS and -0.11 (95%CI: -0.17, -0.04) for PFHxS]. 6:2 Cl-PFESA showed negative associations with total motility (-2.33, 95%CI: -3.80, -0.86) and progressive rate (-1.46, 95%CI: -2.79, -0.12). But perfluoroheptanesulfonic acid (PFHpS) was positively associated with sperm count and concentration. These associations were supported by the importance assessment of these four congeners in XGBoost analyses. However, no associations were found between PFAS mixture or branched isomers and semen quality; nor were there significant interactions among PFAS congeners.
Conclusions
In the current cross-sectional study, we found that two emerging PFAS replacements (i.e.,6:2 Cl-PFESA and PFBS) and PFHxS exposure were associated with reduced semen concentration, total sperm count and motility in men. Meanwhile, significant positive associations between PFHpS and sperm count and concentration were also observed. But there were no consistent associations between PFAS mixture, branched isomers and semen quality.
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