Effects of manganese on routine semen quality parameters: results from a population-based study in China

BACKGROUND: Manganese (Mn) is an essential element in humans but its effect on semen quality is unclear. This study therefore aimed to assess the effects of Mn on semen quality in healthy men with no occupational exposure to Mn. METHODS: Semen samples were obtained from healthy Chinese men 20–59 years old who were recruited from six provinces in China. Individuals with urogenital tract diseases, tuberculosis, or occupational exposure to heavy metals were excluded. A questionnaire survey was conducted, and the external genitalia, semen quality, and serum Mn levels were examined. RESULTS: A total of 1,179 volunteers were enrolled in this study. The median serum Mn concentration was 8.2 μg/L (25th percentile (P(25))=3.7 μg/L, P(75)=16.2μg/L). After adjusted area (six provinces), abstinence interval, season, registered residence, age of subjects, education level, income, smoking, and drinking, the risk of teratospermia was increased at serum Mn concentrations >19.40 μg/L (P(80)) group, with an adjusted odds ratio of 2.27 (95% confidence interval: 1.18–4.37). CONCLUSION: High serum Mn levels appeared to have harmful effects on sperm morphology and motility among healthy men with no occupational exposure to Mn.