25(OH)D was Correlated with Increased Risk of Insulin Resistance, but Not Mediated by Adiponectin and hsCRP

Abstract

BACKGROUND: Studies have shown that change of calcium and vitamin D homeostasis is associated with insulin resistance, decreased beta cell function, metabolic syndrome, glucose intolerance and diabetes. Evidence suggests that vitamin D insufficiency is inversely related to risk of metabolic disorders including type-2 Diabetes Mellitus (T2DM), although the underlying mechanisms are not yet understood. Hence, current study was conducted to investigate correlation between 25(OH)D and insulin resistance through adiponectin or High Sensitivity C-Reactive Protein (hsCRP) in centrally obese men.

METHODS: This was a cross-sectional study involving 80 centrally obese men with waist circumference (WC) >90 cm and age 30-60 years. Total 25(OH)D concentration was measured by Enzyme-Linked Immunosorbent Assay (ELISA) method. Insulin resistance was calculated by HOMA model.

RESULTS: This study showed there was no correlation of 25(OH)D-WC (r=0.006 and p=0.957), 25(OH)D-adiponectin (r=0.179 and p=0.111) abd 25(OH)D-hsCRP (r=-0.223 and p=0.334), but we observed  statistically significant negative correlation between 25(OH)D and insulin resistance index (HOMA-IR) (r=0.461 and p=0.041).

CONCLUSIONS: We conclude that low 25(OH)D concentration was significantly associated with increased risk of insulin resistance. Since  the adiponectin or hsCRP was not correlated, the possible pathways need to be futher investigated.

KEYWORDS: central obesity, 25(OH)D, adiponectin, hsCRP, insulin resistance (HOMA-IR)