Associations between the composite dietary antioxidant index and abdominal aortic calcification among United States adults: A cross-sectional study.

BACKGROUND:Oxidative stress has previously been shown to play a pivotal role in the pathogenesis of vascular calcification. In the present study, we aimed to investigate the association between the composite dietary antioxidant index (CDAI) and abdominal aortic calcification (AAC). METHODS:We conducted a cross-sectional study of United States adults using data from the 2013-2014 National Health and Nutrition Examination Survey. The CDAI was calculated from vitamins A, C, E, selenium, zinc, and caretenoid through two rounds of 24-h dietary recall interviews. AAC was assessed by a lateral dual-energy x-ray absorptiometry scan of the thoraco-lumbar spine. The association between CDAI and AAC was evaluated with weighted multivariable logistic regression. RESULTS:Overall, an unweighted 1081 participants were analyzed, including 110 with AAC and 971 without AAC. In the multivariable fully adjusted logistic regression model, CDAI was significantly associated with AAC (odds ratio = 0.89, 95% CI 0.81-0.98; P = 0.02). Compared with the lowest quartile, the highest quartile of CDAI was related to a 0.33-fold risk of AAC (95% CI 0.12-0.90; P = 0.03). Subgroup analysis showed that the significant association between CDAI and AAC was only observed in participants without hypertension (P for interaction = 0.002). CONCLUSION:A higher CDAI was associated with a lower prevalence of AAC among adults without hypertension in the US. Further large-scale prospective studies are required to analyze the protective role of the CDAI in AAC progression.