Association between dietary antioxidant intakes and chronic respiratory diseases in adults

Background: Chronic respiratory diseases (CRDs) pose a significant global health burden. Antioxidant-rich diets have been associated with improved lung health, but the specific relationship with CRDs remains unclear. Methods: This study examined the relationship between dietary antioxidant intakes and CRDs using data from the 2001-2018 National Health and Nutrition Examination Survey (NHANES). Information on dietary antioxidant intakes, including vitamins A, C, and E, zinc, selenium, and carotenoid, were collected from the 2 24-h recall interviews to calculate composite dietary antioxidant index (CDAI). CRDs were determined based on self-reported physician diagnoses. To examine the relationship between CDAI and CRDs, multivariate logistic regression was used. To study potential non-linear correlations within these associations, restricted cubic spline (RCS) regression was performed. Results: The study involved 40 557 individuals. The median CDAI was -0.09 (-2.05, 2.25). We discovered those who were in the fourth quartile of CDAI scores had a 19% lower prevalence than those in the first quartile (OR = 0.81 [0.72-0.91], P-trend < 0.01) after adjusting for all relevant covariates. The fourth quartile of CDAI was linked with a lower prevalence of emphysema (OR = 0.57 [0.40-0.81], P-trend < 0.01) and chronic bronchitis (OR = 0.74 [0.62-0.88], P-trend < 0.01). RCS regression showed that CDAI was non-linearly related to the prevalence of CRDs, with inflection points of 3.20 (P for non-linearity <0.01). The stratified analysis did not identify variables that significantly affected the results. Conclusion: Higher dietary antioxidant intakes were related with a lower prevalence of CRDs (particularly emphysema and chronic bronchitis) in general adults.