Vitamin D deficiency, vitamin D receptor gene polymorphisms and cardiovascular risk factors in Caribbean patients with type 2 diabetes

Abstract

Aim The prevalence of diabetes in the French West Indies is three times higher than in mainland France. We aimed to assess the associations between vitamin D deficiency, vitamin D receptor ( VDR) gene polymorphisms and cardiovascular risk factors in Caribbean patients with type 2 diabetes (T2D). Methods In this cross-sectional study of 277 patients, 25-hydroxyvitamin D was measured by radioimmunoassay. FokI, BsmI, ApaI and TaqI single nucleotide polymorphisms (SNPs) of the VDR gene were genotyped. Analysis of covariance and logistic regression were performed. Results The study included 76 patients of Indian descent and 201 patients of African descent. The prevalence of vitamin D deficiency (< 20 ng/mL) was 42.6%. When patients were classified into groups with (G1) and without (G2) vitamin D deficiency, there were no significant differences in age, systolic blood pressure, low-density lipoprotein cholesterol and HbA 1c, although body mass index was significantly higher in G1. Vitamin D deficiency was significantly associated with increased diastolic blood pressure and triglyceride levels, and reduced high-density lipoprotein cholesterol ( P < 0.05). Prevalence of vitamin D deficiency was decreased in patients carrying the f allele of FokI (OR: 0.52; P = 0.02) and the aa genotype of ApaI (OR: 0.46; P = 0.05). BsmI and TaqI SNPs were not associated with vitamin D deficiency. Conclusion The rate of vitamin D deficiency was high in our T2D patients, and was associated with the VDR gene FokI and ApaI polymorphisms and cardiovascular risk profile. Measurements of vitamin D may help to detect T2D patients with cardiovascular risk, and VDR polymorphisms might explain why vitamin D deficiency is so frequently seen in some T2D patients.