Association between Composite Dietary Antioxidant Index and sarcopenia in U.S. middle-aged and older adults: A cross-sectional study

This study aimed to investigate the relationship between the Composite Dietary Antioxidant Index (CDAI) and sarcopenia in middle-aged and older adults using data from the 1999 to 2018 National Health and Nutrition Examination Survey. The study included 6621 participants from National Health and Nutrition Examination Survey. CDAI was calculated based on dietary data from the first 24-hour dietary recall, reflecting the intake of 6 major antioxidants: vitamins C, E, and A, carotenoids, zinc, and selenium. Sarcopenia was defined using the sarcopenia index, calculated as appendicular skeletal muscle mass adjusted for body mass index, with cutoff values from the Foundation for the National Institutes of Health. Multivariable logistic regression analyses were conducted to assess the relationship between CDAI and sarcopenia risk. Among 6621 adults aged ≥ 40 years, the overall prevalence of sarcopenia was 12.3%. Participants in the highest CDAI quartile had a lower prevalence of sarcopenia (8.2%) compared to the lowest quartile (17.1%, P < .001). In multivariable analyses, CDAI was inversely associated with sarcopenia risk. Each 1-unit increase in CDAI was linked to a 7% reduction in sarcopenia odds (odds ratio = 0.93, 95% confidence interval = 0.91-0.95, P < .001). Compared with the lowest quartile, the highest CDAI quartile showed a 53 % lower odds of sarcopenia (odds ratio = 0.47, 95% confidence interval = 0.32-0.70, P < .001). Dose-dependent risk reductions were observed across CDAI quartiles. Subgroup analyses showed consistent inverse associations across various categories, with no significant interactions. Sensitivity analyses confirmed the robustness of the findings. Higher CDAI levels are associated with a lower risk of sarcopenia in middle-aged and older adults. This study highlights the potential protective role of dietary antioxidants in maintaining muscle health and preventing sarcopenia. Future research should explore causal relationships and specific mechanisms, and validate findings in diverse populations.