Cross-sectional associations between multiple plasma heavy metals and lung function among elderly Chinese

Environmental exposure to heavy metals may adversely affect lung function particularly in the elderly. However, limited data are available directly evaluating the relationship of heavy metal exposures with lung function in Chinese elderly. We aimed to investigate the associations between plasma metals and lung function among Chinese elderly residents. We conducted a cross-sectional study of 308 elderly residents in an industrial area and a non-industrial area in northwest China and estimated the single and combined effects of plasma metals and their interactions with lung functions (forced vital capacity [FVC], forced expiratory volume in 1 s [FEV1], and FEV1/FVC). We analyzed 12 plasma metals and identified 4 metals by lasso regression and BKMR model for further analysis. Bayesian kernel machine regression (BKMR) and quantile-g computation (QG-comp) models estimated four metals that had greater importance in lung function indicators, namely strontium (Sr), chromium (Cr), cobalt (Co) and nickel (Ni). Subgroup analyses were performed based on the resident areas. Both BKMR and QG-comp models showed metal mixtures was positively associated with FEV1/FVC (0.046 [0.017,0.075]) among all participants but of negative association with FVC, and similar results were found among participants in non-industrial area. The subgroup analysis by region showed higher heavy metal levels in industrial areas than non-industrial area. Sr concentrations were lower in non-industrial area, but they had a negative effect on FVC. In conclusion, plasma Sr, Cr, Co, and Ni levels are significant associated with lung function particularly with restrictive ventilatory dysfunction among the Chinese elderly population.