Association between the composite dietary antioxidant index and urinary phthalate concentrations: Evidence from...

The relationship between the Composite Dietary Antioxidant Index (CDAI) and urinary phthalate concentrations has yet to be explored. This study utilized data from the 2011-2018 NHANES database. Weighted multivariable linear regression models were employed to examine the relationship between CDAI and urinary phthalate concentrations. Subgroup analyses were conducted to explore differences in associations across various subgroups. Additionally, restricted cubic spline (RCS) analyses were performed to investigate potential nonlinear relationships between CDAI and urinary phthalate concentrations. In the multivariable linear regression model, fully adjusted for confounding variables, CDAI was significantly associated with lower concentrations of high-molecular-weight (HMW) phthalates, including MCOP (β = -0.724, 95% CI: -1.454, -0.006) and MECP (β = -0.297, 95% CI: -0.618, -0.091). MBzP also showed a significant negative association with CDAI (β = -0.212, 95% CI: -0.353, -0.071). For low-molecular-weight (LMW) phthalates, there was a significant association between CDAI and lower MiBP concentrations (β = -0.136, 95% CI: -0.318, -0.046). Subgroup analyses indicated a negative correlation between CDAI and urinary phthalate concentrations in participants aged 60 years and older, as well as in male participants. Weighted RCS analysis demonstrated a linear relationship between CDAI and urinary phthalate concentrations. CDAI negatively correlated with urinary phthalate concentrations; further research is needed for validation.