Association between composite dietary antioxidant index and hypertension: insights from NHANES

Aim The association between composite dietary antioxidant index (CDAI) and hypertension remains unknown. Our study was to investigate the association of CDAI with hypertension in general adults. Methods A total of 21 526 participants were enrolled from the National Health and Nutrition Examination Surveys (NHANES). The CDAI was calculated from the intake of six dietary antioxidants. Multivariable logistic regressions were performed to explore the associations between CDAI and the prevalence of hypertension. Non-linear correlations were explored using restricted cubic splines. And the inflection point was determined by the two-piecewise linear regression. Results In the multivariate logistic regression model with full adjustment for confounding variables, the odds ratio (95% confidence interval) of CDAI associating with hypertension was 0.98 (0.97-1.00; P = .016). Besides, compared to the lowest quartile, the highest quartile of CDAI was associated with a lower risk of hypertension (0.81 [0.70-0.94]; P = .006). Furthermore, a linear association was found by restricted cubic spline, with 3.4 being the turning point. Conclusion Our study highlighted a negative linear association between CDAI and hypertension in general adults.