Exposure to endocrine-disrupting metals and serum estrogen levels among US women

Multiple factors could affect estrogen levels in the body; however, the impact of exposure to endocrine-disrupting chemicals on estrogen levels in humans remains inconclusive. This cross-sectional study was to assess the association between blood levels of endocrine-disrupting metals (including cadmium, lead, and mercury) and serum estradiol levels in 1618 women (aged ≥ 20 years) who participated in the 2013-2016 National Health and Nutrition Examination Survey. Using multiple general linear models, we estimated percent changes of estradiol levels in association with blood metal concentrations. Age-specific analysis was further conducted. The median level of blood cadmium, lead, and mercury was 0.31 µg/L (range: 0.07-7.23), 0.76 µg/dL (0.11-12.80), and 0.73 µg/L (0.20-36.90), respectively, and the median estradiol level was 31.10 pg/mL (range: 2.12-523.00) among women aged 20-80 years. After adjusting for potential confounders, a 10 % increase in blood cadmium and lead levels was associated with 1.43 % (95 % CI: 0.50, 2.37) increased levels and 1.45 % (- 2.17, - 0.11) decreased levels of estrogen, respectively, in the total study population. When stratified by age, the positive association with cadmium was only seen in women aged 20-49 years [1.47 % (0.39, 2.56) increased estradiol] and the inverse association with lead was seen among women aged 50-80 years [3.40 % (- 4.78, - 2.00) decreased estradiol]. Mercury was not significantly associated with estrogen levels. Our study demonstrates a potential relationship between exposure to endocrine-disrupting cadmium and lead and serum estrogen levels in US women. Age-specific associations were observed. Prospective and mechanistic studies are warranted to further explore these interactions and the associated reproductive toxicities.