Association between serum vitamin D and insulin resistance in African Americans with type 2 diabetes (1030.3)

Abstract

The purpose of the study was to determine the association between serum vitamin D and insulin resistance measured by HOMA2‐IR index in a sample of African Americans with type 2 diabetes residing in South Florida. Subjects were recruited by community outreach. One hundred and eleven subjects (n=111) were included in the study. Fasting plasma insulin and glucose were used to calculate HOMA2‐IR. Serum vitamin D was measured with an enzyme‐immunoassay kit by absorbance. HOMA2‐IR values were log transformed to achieve normality. Unadjusted and adjusted multilinear regressions were used to determine the association between log HOMA2‐IR and serum vitamin D. Log HOMA2‐IR was the dependent variable. The mean age, BMI, A1C, energy intake, serum vitamin D, and log HOMA2‐IR values were 54.73 ± 10.21 years, 35.90 ± 8.22 kg/m2, 7.61 ± 1.92 (%), 2088.47 ± 1116.58 kcal, 19.12 ± 8.86 (ng/mL), and 0.22 ± 0.29 respectively. In the unadjusted model, serum vitamin D was associated with log HOMA2‐IR (β=‐0.203, P=0.030). However, the association did not hold after adjusting for covariates (P=0.109). Age (P=0.020), BMI (P=0.001), and A1C (P=0.002) were strongly associated with HOMA2‐IR. The association among serum vitamin D and HOMA2‐IR was confounded by age, BMI and A1C.Grant Funding Source: Supported by NIH/NIDDK sponsored grant. JE was supported by NIH/NIGMS R25 GM061347.