The Relationship between Metal Exposure and Chronic Obstructive Pulmonary Disease in the General US Population: NHANES 2015–2016

The effects of metal on pulmonary function are inconsistent, and abnormal distribution of metals can decrease lung function. However, the effects of metals exposure on chronic obstructive pulmonary disease (COPD) are still unclear. This study aims to explore the relationship between metal exposure and COPD risk. Cross-sectional data from the National Health and Nutrition Survey (NHANES) 2015–2016 was analyzed. Inductively coupled plasma dynamic reaction cell mass spectrometry (ICP-DRC-MS) was used to measure the metals concentration in the blood. The multiple linear regression and restricted cubic spline (RCS) were used to analyze the relationship between metals exposure and COPD risk. In this study, 1399 participants were included, of which 107 participants were diagnosed with COPD using self-reported chronic bronchitis, emphysema, and COPD. The second and third tertiles of copper increased the COPD risk by 1.98-fold (95% CI: 1.08–3.62) and 2.43-fold (95% CI: 1.32–4.48) compared with the first tertile, using p = 0.005 for the trend after adjusting for the covariates. RCS showed a positive linear correlation between copper and COPD risk (p = 0.006 for overall association) in all participants. When stratified by sex, the multi-factor analysis showed that the third tertile of copper increased male’s COPD risk by 3.42-fold (95% CI: 1.52–7.76), with p = 0.003 for the trend, and RCS also showed a positive linear correlation (p = 0.013 for overall association). Although RCS showed that selenium can reduce the COPD risk (p = 0.008 for overall association) in males, an association between selenium and COPD was not observed (p > 0.05). Our findings suggest that a high concentration of copper may increase COPD risk in males in the general US population, and more research is needed to explore its possible mechanism of action.