Association of background-level arsenic exposure with sperm quality and sex hormones in Chongqing males

To study the relationship of urinary total arsenic exposure level with sperm quality and sex hormone levels in young male population, and evaluate the potential impact of background arsenic exposure on parameters of sperm quality and sex hormone levels in Chongqing.

Generalized additive model and recursive algorithm were used to analyze the correlation of the baseline urine arsenic concentration with semen parameters and sex hormone levels in 703 male college students volunteers（18~22 years old）in the cohort of Chongqing college students constructed in 2013-2015. The inflection point of the nonlinear relationship was explored, and the threshold effect of arsenic exposure was analyzed. The median of urinary arsenic in this study was compared with the data from other reports at home and abroad.

There was a nonlinear relationship of urine arsenic level with sperm concentration, sperm total number, sperm DNA fragment index, and levels of prolactin, follicle-stimulating hormone and progesterone. Further threshold effect analysis showed that there were inflection points of urine arsenic concentration with the above indicators, and the key points were 15.17, 14.17, 50.97, 57.51, 11.36, and 70.44 μg/L, respectively（Log-likelihood ratio test P<0.05）. Compared with relevant literature, the urine arsenic level was at a relatively lower level in this cohort population.

Compared with some regions at home and abroad, the background urine arsenic level of this study population is quite lower, and significant correlation is found in the background level with the decline of sperm quality parameters and changes in sex hormone levels.