Vitamin D Deficiency and Cardio-Metabolic Risk in a North Indian Community with Highly Prevalent Type 2 Diabetes

Objective: The purpose of this investigation was to examine serum vitamin D status in a population of Punjabi ancestry from Northern India with a high prevalence of type 2 diabetes (T2D) and evaluate the effects of 25(OH) D levels on cardio-metabolic traits. Research design and methods: We assessed cardiovascular risk factors and 25(OH) D levels in 1,765 participants (887 T2D cases, 878 normoglycemic controls). Results: 76% of individuals were deficient (< 50 nmol/L) in vitamin D. A higher percentage of T2D participants(83%) were vitamin D deficient compared to normoglycemic controls (68%)(p< 0.0001). The prevalence of vitamin D deficiency increased progressively with body mass index (BMI) categories (p< 0.0001): BMI< 23 kg/m(2), 65%; BMI 23-27.5 kg/m(2), 75%; and BMI> 27.5 kg/m(2), 81%. T2D participants had significantly decreased serum 25(OH) D levels (beta=-0.41, p= 2.8 x 10(-20)). Individuals with low serum 25(OH) D had elevated fasting glucose(beta=-0.18, p= 0.022), BMI (beta=-0.71, p= 1.4 x 10(-7)) and systolic blood pressure (beta=-1.68, p= 0.006). A positive association of increased 25(OH) D with HOMA-B (beta= 0.17, p= 8.0x10-6), and C-peptide (beta= 0.09, 0.017) was observed. Non-medicated, normoglycemic, non-hypertensive individuals classified as vitamin D deficient (n= 289) exhibited a significant increase in fasting glucose (p= 0.02) and BMI (p< 0.0001) as well as a significant decrease in C-peptide (p< 0.0001) and amylin (p< 0.0001) compared to vitamin D sufficient controls (n= 150). Conclusions: Vitamin D deficiency appears to be a significant risk factor for T2D severity and associated cardio-metabolic risk. Early intervention may be considered to improve prevention of T2D related cardiovascular complications.