Blood trihalomethane concentrations in relation to sperm mitochondrial DNA copy number and telomere length among 958 healthy men

Chong Liu; Ying-Jun Chen; Bin Sun; Heng-Gui Chen; Vicente Mustieles; Carmen Messerlian; Yang Sun; Tian-Qing Meng; Wen-Qing Lu; Xiong-Fei Pan; Chen-Liang Xiong; Jian Hou; Yi-Xin Wang

doi:10.1016/j.envres.2022.114737

Blood trihalomethane concentrations in relation to sperm mitochondrial DNA copy number and telomere length among 958 healthy men

Environ Res. 2023 Jan 1;216(Pt 4):114737. doi: 10.1016/j.envres.2022.114737. Epub 2022 Nov 11.

Authors

Chong Liu¹, Ying-Jun Chen², Bin Sun³, Heng-Gui Chen⁴, Vicente Mustieles⁵, Carmen Messerlian⁶, Yang Sun⁶, Tian-Qing Meng⁷, Wen-Qing Lu¹, Xiong-Fei Pan⁸, Chen-Liang Xiong⁹, Jian Hou¹⁰, Yi-Xin Wang¹¹

Affiliations

¹ Key Laboratory of Environment and Health, Ministry of Education & Ministry of Environmental Protection, And State Key Laboratory of Environmental Health (incubating), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, PR China; Department of Occupational and Environmental Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, PR China.
² Department of Epidemiology, School of Public Health, Southern Medical University, Guangzhou, PR China.
³ Key Laboratory of Environment and Health, Ministry of Education & Ministry of Environmental Protection, And State Key Laboratory of Environmental Health (incubating), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, PR China.
⁴ Clinical Research and Translation Center, The First Affiliated Hospital, Fujian Medical University, Fuzhou, PR China.
⁵ University of Granada, Center for Biomedical Research (CIBM); Consortium for Biomedical Research in Epidemiology & Public Health (CIBERESP), Madrid, Spain.
⁶ Department of Epidemiology and Environmental Health, Harvard T.H. Chan School of Public Health, Boston, MA, USA.
⁷ Hubei Province Human Sperm Bank, Center of Reproductive Medicine, Wuhan Tongji Reproductive Medicine Hospital, Wuhan, PR China.
⁸ Key Laboratory of Birth Defects and Related Diseases of Women and Children (Sichuan University), Ministry of Education, West China Second University Hospital, Sichuan University, Chengdu, PR China.
⁹ Hubei Province Human Sperm Bank, Center of Reproductive Medicine, Wuhan Tongji Reproductive Medicine Hospital, Wuhan, PR China. Electronic address: clxiong951@sina.com.
¹⁰ Department of Epidemiology and Biostatistics, School of Public Health, Zhengzhou University, Zhengzhou, PR China. Electronic address: houjian1988@zzu.edu.cn.
¹¹ Department of Epidemiology and Environmental Health, Harvard T.H. Chan School of Public Health, Boston, MA, USA; Department of Nutrition, Harvard T.H. Chan School of Public Health, Boston, MA, USA. Electronic address: yixinwang@hsph.harvard.edu.

PMID: 36372149
DOI: 10.1016/j.envres.2022.114737

Abstract

Background: In animal and human studies, exposure to trihalomethanes (THMs) has been associated with reduced semen quality. However, the underlying mechanisms remain poorly understood.

Objective: To investigate the associations of blood THM concentrations with sperm mitochondrial DNA copy number (mtDNAcn) and telomere length (TL) among healthy men.

Methods: We recruited 958 men who volunteered as potential sperm donors. A single blood sample was collected from each participant at recruitment and measured for chloroform (TCM), bromodichloromethane (BDCM), dibromochloromethane (DBCM), and bromoform (TBM) concentrations. Within a 90-day follow-up, the last semen sample provided by each participant was quantified for sperm mtDNAcn and TL. We used multivariable linear regression models to assess the associations between blood THM concentrations and sperm mtDNAcn and TL. We also performed stratified analyses according to the time intervals between baseline blood THM determinations and semen collection (i.e., 0-9, 10-14, 15-69, or >69 days) to explore potential windows of susceptibility.

Results: After adjusting for potential confounders, we found inverse associations between quartiles (or categories) of blood TBM, brominated THM (Br-THM, the sum of BDCM, DBCM, and TBM), and total THM (TTHM, the sum of all four THMs) concentrations and sperm mtDNAcn (all P for trend≤0.03). Besides, we found inverse associations between quartiles of blood TCM, Br-THM, chlorinated THM (Cl-THM, the sum of TCM, BDCM, and DBCM), and TTHM concentrations and sperm TL (all P for trend<0.10). Stratified analyses showed stronger associations between Br-THM concentrations and sperm mtDNAcn determined 15-69 days since baseline exposure determinations, and between blood TCM and TTHM concentrations and sperm TL determined >69 days since baseline exposure determinations.

Conclusion: Exposure to THMs may be associated with sperm mitochondrial and telomeric dysfunction.

Keywords: Disinfection by-products; Mitochondrial DNA copy Number; Sperm donors; Telomere length; Trihalomethanes.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

DNA Copy Number Variations
DNA, Mitochondrial
Humans
Male
Semen / chemistry
Semen Analysis*
Spermatozoa
Telomere
Trihalomethanes / toxicity
Water Pollutants, Chemical* / analysis

Substances

DNA, Mitochondrial
bromodichloromethane
chlorodibromomethane
Trihalomethanes
Water Pollutants, Chemical