Association of dietary antioxidant indices with kidney function indicators in patients with type 2 diabetes: a cross-sectional study

This cross-sectional study investigated the relationship between dietary antioxidant indices and kidney function indicators in 240 outpatient adults with type 2 diabetes. Dietary intake was assessed using three 24-h dietary recalls. Dietary total antioxidant capacity (DTAC), dietary antioxidant index (DAI), and dietary antioxidant quality score (DAQS) were obtained. Indicators of kidney function, including serum creatinine, urea, blood urea nitrogen (BUN), and glomerular filtration rate (GFR), were extracted from medical records. After adjustment, the highest DAI tertile had lower serum creatinine (0.98 ± 0.27 vs 1.03 ± 0.32 mg/dL, P < 0.001), reduced urea (30.97 ± 8.75 vs 34.07 ± 14.45 mg/dL, P = 0.005), and higher GFR (85.16 ± 29.43 vs 74.16 ± 22.18 ml/min per 1·73 m2, P < 0.001) compared to the lowest tertile. The results of logistic regression analysis indicated a borderline significant inverse association of serum urea > 20 mg/dl with DTAC (odds ratio (OR):0.28; 95% CI: 0.07-1.09; P_trend = 0.06). Multivariable linear regression analysis revealed a significant aligned correlation between DAQs and GFR (β: 0.20; P-value: 0.005) and a marginally significant direct relationship between DAI and GFR (β: 0.14; P-value: 0.06). However, no significant association was observed for DTAC with GFR (β:-0.02; P-value: 0.80). Diets with higher antioxidant capacity may be linked to improved kidney function in type 2 diabetes but our results did not support this strongly.