Endocrine-disrupting metals in ambient air and female breast cancer incidence in US

Metals could act as endocrine disruptors that mimic the actions of hormones, such as estrogens, and contribute to the development and progression of breast cancer. In this study, we examined the association between ambient air emissions of several endocrine-disrupting metals and the incidence of female breast cancer in the United States by analyzing county-level data from national datasets. Linear regression analysis was conducted to evaluate the association in unadjusted and adjusted models. Of the metals analyzed, air emissions of arsenic, cadmium, lead, and mercury, but not chromium VI, were significantly associated with the incidence of all breast cancers, after adjusting for potential confounders. Emissions of arsenic, lead, and mercury were found to be significantly associated with the incidence of estrogen receptor (ER)-positive breast cancer. Among these metals, air emissions of lead showed the strongest association with breast cancer incidence with the beta of 3756.66 (95% CI: 1660.29, 5853.03) for all breast cancers and 2433.85 (440.59, 4427.10) for ER-positive breast cancer. Our results demonstrate that exposure to endocrine-disrupting metals in ambient air may be associated with an increased incidence of breast cancer in the United States. Further studies are needed to explore these interactions and to elucidate mechanisms of action.