Association Between Serum Copper and COPD: Insights from NHANES 2011-2016 and Mendelian Randomization Study

While elevated serum copper is associated with COPD prevalence observationally, the null MR finding suggests it may reflect tobacco-related systemic oxidative stress or reverse causation rather than being a direct causal driver. Therefore, serum copper may be more useful as a biomarker of smoking-induced redox disturbance than as a therapeutic target. These results underscore the importance of integrating tobacco exposure metrics in future studies examining metal biology in COPD.