Association between composite dietary antioxidant index and cataract in American adults aged ≥50 years: A cross-sectional study from NHANES 2003-2008.

Oxidative stress is one of the crucial pathogeneses of cataract. The composite dietary antioxidant index (CDAI) represents the antioxidant capacity of one's diet. The aim of this study was to explore the association between the CDAI and cataract. The data were obtained from the National Health and Nutrition Examination Survey 2003 to 2008. A weighted multiple logistic regression, generalized weighted models, and smoothed fitted curves were performed to investigate the association between the CDAI and cataract. A total of 5814 participants aged ≥50 years with complete data were included in the study. According to the fully adjusted model, the odds ratio (95% confidence interval) for the association between the CDAI and cataract was 0.95 (0.93, 0.98). After dividing continuous CDAI into tertiles, consistent negative associations between CDAI and cataract were observed in the highest tertile compared to the lowest tertile (odds ratio = 0.77; 95% confidence interval, 0.62-0.95). The CDAI components (zinc, magnesium, vitamin A, and vitamin E) were also negatively associated with cataract odds in the fully adjusted model. Subgroup analysis showed inconsistent associations among subgroups, but no statistically significant interaction effects were found. This cross-sectional study revealed that a higher CDAI was associated with lower odds of cataract. These findings may contribute to cataract prevention through antioxidant dietary patterns.