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

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.