Urinary concentrations of environmental metals and associating factors in pregnant women.

Pregnant women, a vulnerable population, can be exposed to a variety of environmental metals that may adversely affect their health at elevated concentrations. Moreover, environmental exposure and risk disparities are associated with several factors such as sociodemographic characteristics, pregnancy complications, and nutritional supplementation indicators. Our aim was to investigate whether and how the urinary metal concentrations vary according to these factors in a large pregnancy and birth cohort. Urinary levels of seven metals including manganese, zinc, selenium, arsenic, cadmium, thallium, and lead were assessed in 7359 participants across Wuhan City in China. In all, 7359 urine samples from the third trimester were analyzed and 15 sociodemographic characteristics, pregnancy complications, and nutritional supplementation indicators were assessed: maternal age, household income, multivitamin supplements during pregnancy, etc. Concentrations of Zn, As, and Cd were detected in all urine samples; Mn, Se, Tl, and Pb were detected in 95.3%, 99.8%, 99.8%, and 99.9% urine samples, respectively. The geometric mean (GM) of creatinine-adjusted urinary Mn, Zn, Se, As, Cd, Tl, and Pb concentrations were 1.42, 505.44, 18.24, 30.49, 0.64, 0.55, and 3.69 μg/g. Factors that associated with environmental metals concentration were as follows: (1) Urinary Zn and Cd concentrations increased with maternal age. (2) Pregnant women with higher education had lower Cd concentrations. (3) Pregnant women with folic acid supplementation had lower Mn and with multivitamin supplementation had higher Se and lower Tl. Our results demonstrated that the maternal age, education level, folic acid supplementation, and multivitamin supplementation were significantly associated with environmental metal concentrations. Furthermore, studies are recommended to explore the influence of diet on biological metals concentrations in more detail.