Composite Dietary Antioxidant Index is negatively associated with olfactory dysfunction among adults in the United States: A cross-sectional study

The Comprehensive Dietary Antioxidant Index (CDAI) plays a crucial role as an indicator of diets rich in antioxidants. Despite its importance, the clinical significance of CDAI concerning olfactory dysfunction (OD) remains unknown. Our study aims to investigate whether there is an association between CDAI and OD within the general adult population aged 20 years and older. We hypothesized a negative correlation between CDAI and OD in the general adult population. A cross-sectional study used data from the National Health and Nutrition Examination Survey (n = 1624; >20 y of age). A multivariate logistic regression model examined the connection between CDAI and OD. Smooth-fitted curves were used to investigate the nonlinear relationship between CDAI and OD. A threshold effect analysis was then used to pinpoint the inflection point. Subgroup analyses were conducted based on gender and age. Multivariate regression analysis revealed a negative correlation between CDAI and OD. After controlling for variables, the risk of OD in the highest quartile of CDAI was significantly lower than in the lowest quartile (Q1) (odds ratio = 0.64; 95% confidence interval, 0.44–0.92; P = .0148). Stratified analysis indicated a significant association between CDAI and OD in individuals younger than age 60 years and male. This research suggests that increasing the co-ingestion of antioxidants within a moderate range can reduce the incidence of OD.