Dietary Antioxidant Intake and Sleep Quality: Combined Effects on Chronic Obstructive Pulmonary Disease in <scp>NHANES</scp> 2005–2008 and Mendelian Randomization Analysis

Both dietary antioxidant quality score (DAQS) and sleep quality are associated with chronic obstructive pulmonary disease (COPD), but their joint influence remains unclear. This investigation examined the associations among DAQS, sleep quality, and COPD in the US adult population utilizing data from the National Health and Nutrition Examination Survey (NHANES). Data from 8752 individuals participating in the NHANES 2005-2008 cycles were analyzed. The associations between COPD risk and both individual and joint effects of DAQS and Pittsburgh Sleep Quality Index (PSQI) were examined using multivariate logistic regression and subgroup analyses. Additionally, potential causal links were explored through two-sample and multivariable Mendelian randomization (MR) analysis. After adjusting for confounders, higher DAQS was negatively associated with COPD (OR = 0.92, 95% CI: 0.85-0.99, <i>p</i> = 0.029), while PSQI was positively related (OR = 1.07, 95% CI: 1.05-1.09, <i>p</i> < 0.001). Relative to individuals with low DAQS and poor sleep quality, the OR for COPD was 0.68 (95% CI: 0.48-0.98) in those with high DAQS and poor sleep quality; 0.54 (95% CI: 0.37-0.79) with low DAQS and good sleep quality; and 0.45 (95% CI: 0.29-0.69) with high DAQS and good sleep quality. Mendelian randomization analysis suggested causal effects of variation in diet and sleep duration on COPD. Based on analyses of a large, nationally representative dataset and Mendelian Randomization studies, our research demonstrated significant associations between DAQS, sleep quality, and COPD. This study is the first to establish the synergistic effect of high DAQS and good sleep quality in mitigating the risk of developing COPD.