Associations of serum Cu, Zn, and Se with Chronic Respiratory Diseases in the American adults: Data from NHANES 2013–2016 and a bidirectional Mendelian randomization analysis

Abstract

Background Despite studies on trace metals and Chronic Respiratory Diseases (CRDs), their causal relationship in American adults is uncertain. Our research applied observational and bidirectional Mendelian randomization (MR) methods to ascertain this association. Objective The aim of this study was to evaluate the potential linkages between serum levels of copper (Cu), zinc (Zn), and selenium (Se) and the incidence of chronic respiratory diseases within the adult demographic of the United States. Methods Drawing on the National Health and Nutrition Examination Survey (NHANES) 2013–2016 data, our study incorporated 2807 adults to examine serum Cu, Zn, and Se impacts on CRDs risks using logistic regression and cubic spline analysis. Subsequently, bidirectional MR assessments were conducted to ascertain the causative linkages pertaining to these associations. Results Employing adjusted-weighted logistic models, high serum Cu significantly escalated the risks for emphysema (OR: 3.83) and Chronic obstructive pulmonary disease (COPD) (OR: 2.14–3.33), while elevated Cu and Zn levels corresponded to respective OR of 1.82 and 1.91 for chronic tracheitis and COPD. Conversely, moderate Se reduced tracheitis risk (OR: 0.64). MR indicated no genetic causation between Cu and respiratory diseases (p > 0.05), yet Cu exposure was causally linked to COPD (p = 0.003), as was Zn (p = 0.014). selenium’s protective genetic association with chronic tracheitis was confirmed (p = 0.010). Conclusion High serum Cu links to increased emphysema, tracheitis, and COPD risk; Zn equally raises COPD risk; Se may lessen tracheitis risk. This observation warrants confirmation through additional large-scale, prospective cohort studies with sufficient sample sizes and extended follow-up durations.