title: Low-level environmental arsenic exposure correlates with unexplained male infertility risk.
abstract: Humans are exposed to arsenic via drinking water, dietary intake and inhaled particulates. Endemic chronic arsenic exposure related reproductive toxicity is well documented, but the effect of low-level general environmental arsenic exposure on unexplained male infertility (UMI) remains unclear. In this case-control study, we aimed to investigate the relationship between non-geogenic environmental arsenic exposure and UMI risk. One hundred and one infertile men with normal semen as cases and sixty one fertile men as controls were recruited. Five urinary arsenic species: pentavalent arsenate (Asi(V)), trivalent arsenite (Asi(III)), methylated to monomethylarsonic acid (MMA(V)), dimethylarsinic acid (DMA(V)), arsenobetaine (AsB) were quantitatively measured by liquid chromatography-inductively coupled plasma-mass spectrometry (LC-ICP-MS). To assess the semen quality, semen volume, sperm concentration, total motility, and progressive motility were measured. The nonparametric Mann-Whitney U test was used to compare the differences of arsenic species and index between the case and the control group; we observed that concentrations of Asi(V), AsB, MMA(V), DMA(V), total inorganic As and total As were significantly higher in the cases than the controls. The urine Asi(V) level increased more than twenty folds in case group. Moreover, higher redox index (Asi(V)/Asi(III)) and lower primary arsenic methylation index (PMI=MMA(V)/Asi) were observed for case group. Furthermore, through the logistic regression analysis, we observed that the urine Asi(V) level and PMI were most significantly associated with UMI risk among the observations. Specifically, in comparison to the first quartile, the subjects with higher Asi(V) levels were more likely to exhibit UMI with increasing adjusted odds ratios (AORs) (adjusted by age, body mass index, drinking status and smoking status) of 8.39 [95% confidence interval (CI), 2.59-27.17], 13.12 (95% CI, 3.44-50.12) and 36.51 (95% CI, 8.25-161.66) at the second, third and fourth quartiles, respectively. Also a concentration-dependent decrease of AOR was also observed for PMI in comparison to the fourth quartile: 15.43 [95% CI, 4.28-55.69], 9.69 (95% CI, 2.78-33.78) and 6.93 (95% CI, 2.21-21.76) at the first, second and third quartiles, respectively. These findings provide evidences that low-level environmental arsenic exposure was positively associated with UMI risk.
authors.affiliation: Shanghai Key Laboratory of Functional Materials Chemistry, School of Chemistry & Molecular Engineering, East China University of Science and Technology, Shanghai 200237, China; Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, China.
authors.forename: Xiaofei
authors.initials: X
authors.lastname: Wang
authors.affiliation: Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, China.
authors.forename: Weipan
authors.initials: W
authors.lastname: Xu
authors.affiliation: Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, China.
authors.forename: Qingyu
authors.initials: Q
authors.lastname: Huang
authors.affiliation: Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, China.
authors.forename: Liangpo
authors.initials: L
authors.lastname: Liu
authors.affiliation: Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, China.
authors.forename: Meiping
authors.initials: M
authors.lastname: Tian
authors.affiliation: State Key Lab of Reproductive Medicine, Institute of Toxicology, Key Laboratory of Modern Toxicology of Ministry of Education, School of Public Health, Nanjing Medical University, Nanjing 211166, China.
authors.forename: Yankai
authors.initials: Y
authors.lastname: Xia
authors.affiliation: Shanghai Key Laboratory of Functional Materials Chemistry, School of Chemistry & Molecular Engineering, East China University of Science and Technology, Shanghai 200237, China. Electronic address: weibingzhang@ecust.edu.cn.
authors.forename: Weibing
authors.initials: W
authors.lastname: Zhang
authors.affiliation: Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, China. Electronic address: hqshen@iue.ac.cn.
authors.forename: Heqing
authors.initials: H
authors.lastname: Shen
mesh_terms: D000328:Adult; D001151:Arsenic / Q000378:metabolism*; D001152:Arsenicals / Q000378:metabolism*; D016022:Case-Control Studies; D002681:China; D004781:Environmental Exposure; D006801:Humans; D007248:Infertility, Male / Q000139:chemically induced*; D008297:Male; D011446:Prospective Studies; D055815:Young Adult
chemical_list: D001152:Arsenicals; D001151:Arsenic
keywords: Arsenic; Arsenic methylation; Environmental exposure; Unexplained male infertility