title: Joint effects of trihalomethanes and trichloroacetic acid on semen quality: A population-based cross-sectional study in China.
abstract: Exposure to trihalomethanes (THMs) and haloacetic acids (HAAs) has been individually associated with adverse male reproductive effects; however, their joint male reproductive toxicity is largely unknown. This study aimed to explore the joint effects of THMs and trichloroacetic acid (TCAA) on semen quality in a Chinese population. A total of 337 men presenting to the Reproductive Center of Tongjing Hospital, in Wuhan, China to seek semen analysis were included this study. Baseline blood THMs [chloroform (TCM), bromodichloromethane (BDCM), dibromochloromethane (DBCM), and bromoform (TBM)] and urinary TCAA were analyzed and dichotomized at their median levels. The joint effects of THMs and TCAA on below-reference semen quality parameters were evaluated by calculating the relative excess risk due to interaction (RERI). After adjusting for potential confounders, we found a suggestive synergistic effect between Br-THMs (sum of BDCM, DBCM, and TBM) and TCAA for below-reference sperm count (RERI = 2.14, 95% CI: -0.37, 4.91) (P = 0.076); men with high Br-THMs and TCAA levels (above the median) had 3.31 times (95% CI: 1.21, 9.07) elevated risk of having below-reference sperm count than men with low Br-THMs and TCAA levels (below the median). No apparent joint effects were observed between THMs and TCAA for other semen quality parameters. Our results suggest that co-exposure to Br-THMs and TCAA is associated with additive effects on decreased semen quality. However, further studies in a larger sample size and mechanistic studies are needed to confirm the findings.
authors.affiliation: Department of Occupational and Environmental Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, PR China; Key Laboratory of Environment and Health, Ministry of Education and Ministry of Environmental Protection, State Key Laboratory of Environmental Health (Incubating), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, PR China.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Zeng
authors.affiliation: College of Public Health, University of South China, Hengyang, Hunan, PR China.
authors.forename: Bin
authors.initials: B
authors.lastname: Zhou
authors.affiliation: College of Public Health, University of South China, Hengyang, Hunan, PR China.
authors.forename: Dong-Liang
authors.initials: DL
authors.lastname: He
authors.affiliation: Department of Occupational and Environmental Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, PR China; Key Laboratory of Environment and Health, Ministry of Education and Ministry of Environmental Protection, State Key Laboratory of Environmental Health (Incubating), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, PR China.
authors.forename: Yi-Xin
authors.initials: YX
authors.lastname: Wang
authors.affiliation: Key Laboratory of Environment and Health, Ministry of Education and Ministry of Environmental Protection, State Key Laboratory of Environmental Health (Incubating), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, PR China.
authors.forename: Mu
authors.initials: M
authors.lastname: Wang
authors.affiliation: Department of Occupational and Environmental Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, PR China; Key Laboratory of Environment and Health, Ministry of Education and Ministry of Environmental Protection, State Key Laboratory of Environmental Health (Incubating), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, PR China.
authors.forename: Pan
authors.initials: P
authors.lastname: Yang
authors.affiliation: Department of Occupational and Environmental Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, PR China; Key Laboratory of Environment and Health, Ministry of Education and Ministry of Environmental Protection, State Key Laboratory of Environmental Health (Incubating), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, PR China.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Huang
authors.affiliation: Department of Occupational and Environmental Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, PR China; Key Laboratory of Environment and Health, Ministry of Education and Ministry of Environmental Protection, State Key Laboratory of Environmental Health (Incubating), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, PR China.
authors.forename: Jin
authors.initials: J
authors.lastname: Li
authors.affiliation: Department of Occupational and Environmental Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, PR China; Key Laboratory of Environment and Health, Ministry of Education and Ministry of Environmental Protection, State Key Laboratory of Environmental Health (Incubating), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, PR China. Electronic address: luwq@mails.tjmu.edu.cn.
authors.forename: Wen-Qing
authors.initials: WQ
authors.lastname: Lu
mesh_terms: D000328:Adult; D002681:China; D002725:Chloroform; D003430:Cross-Sectional Studies; D004357:Drug Synergism; D006801:Humans; D008297:Male; D009845:Oligospermia / Q000139:chemically induced; D055101:Semen Analysis; D014238:Trichloroacetic Acid / Q000737:chemistry / Q000633:toxicity*; D022882:Trihalomethanes / Q000737:chemistry / Q000633:toxicity*
chemical_list: D022882:Trihalomethanes; D014238:Trichloroacetic Acid; D002725:Chloroform
keywords: Disinfection by-products; Semen quality; Synergistic effect; Trichloroacetic acid; Trihalomethanes