Cadmium, lead, and mercury interactions on obstructive lung function in pre- and postmenopausal women

There was a dearth of information on how heavy metals affect women's lung function. To assess the effects of cadmium, lead, and mercury and their interactions on obstructive lung function in pre- and postmenopausal women. The associations between an individual heavy metal and its mixtures and the first second of forced expiration (FEV1)/forced vital capacity (FVC) were studied using multivariate non-linear, linear, and logistic regression models, Bayesian kernel machine regression (BKMR), and marginal effects in 1821 women. Serum cadmium and lead levels and the percentage of FEV1/FVC < 70% were substantially higher in postmenopausal women than in premenopausal women. Cadmium (β =  - 0.84, 95%, - 1.63 to - 0.05) and lead (β =  - 0.43, 95%CI, - 1.62 to - 0.04) were found to be inversely associated with the FEV1/FVC ratio in premenopausal women, while a combination of cadmium and mercury showed a negative association with the FEV1/FVC ratio in postmenopausal women (β =  - 0.65, 95%CI, - 1.27 to - 0.03). In the non-linear regression model, an inverted U-shape association of mercury with FEV1/FVC indicator was found in postmenopausal women (β =  - 0.78, 95%CI, - 1.41 to - 0.15). In BKMR model, a mixture of three heavy metals was negatively associated with the FEV1/FVC ratio. Cadmium was identified as an important substance associated with lung function decline (posterior inclusion probabilities (PIPs) = 0.731 in premenopausal and PIPs = 0.514 in postmenopausal women). Cadmium appeared linear; an inverted U-shape association of mercury with the FEV1/FVC indicator and slightly positive associations of lead with the FEV1/FVC indicator in postmenopausal women were found. Threshold cutoff values for the studied substances related to clinical lung function decline were established. In conclusion, the presence of mixed heavy metals (cadmium, lead, and mercury) and their association with obstructive lung function showed worse results than separate associations. These findings have important implications for policy and future research about how heavy metals affect women's lungs.