Independent and combined associations of multiple heavy metal exposure with lung function: A population-based study in US children

Abstract Background: Previous research has found relationships between some single metals and lung function parameters. However, the role of simultaneous multi-metal exposure is poorly understood. The crucial period throughout childhood, when people are most susceptible to environmental dangers, has also been largely ignored. The study aimed to evaluate the joint and individual associations of 12 selected urinary metals with pediatric lung function measures using multipollutant approaches. Methods: A total of 1227 children aged 6–17 years from the National Health and Nutrition Examination Survey database of the 2007–2012 cycles were used. The metal exposure indicators were 12 urine metals adjusted for urine creatinine, including Arsenic (As), Barium (Ba), Cadmium (Cd), Caesium (Cs), Cobalt (Co), Mercury (Hg), Molybdenum (Mo), Lead (Pb), Antimony (Sb), Thallium (Tl), Tu (Tungsten), and Urtiam (Ur). The outcomes of interest were lung function indices including the 1st second of a forceful exhalation (FEV 1 ), forced vital capacity (FVC), forced expiratory flow between 25% and 75% of vital capacity (FEF 25–75% ), and peak expiratory flow (PEF). Multivariate linear regression, quantile g-computation (QG-C), and Bayesian kernel machine regression models (BKMR) were adopted. Results: A significantly negative overall effects of metal mixtures on all four lung function parameters were observed. Pb had the largest negative contribution to the negative associations, and Pb's relationship with lung function metrics showed to be nonlinear, with an approximate "L" shape. Potential interactions between Pb and Cd in lung function decline were observed. Whereas Ba was positively associated with lung function metrics. Conclusion: Metal mixtures were negatively associated with pediatric lung function. Pb might be crucial elements. Our findings highlight the need for prioritizing children’s environmental health to protect them from later respiratory disorders and to guide future research into the toxic mechanisms of metal-mediated lung function injury in the pediatric population.