Vitamin D receptor gene polymorphisms (BsmI and FokI) and serum levels of 25-hydroxyvitamin D in Egyptian patients with type 2 diabetes and their association with atherosclerosis

Background/aim
A large number of individuals with type 2 diabetes mellitus (T2DM) die owing to atherosclerotic cardiovascular diseases (CVD). The role of vitamin D deficiency and vitamin D receptor (VDR) gene polymorphisms in the development of T2DM-related CVD has yet to be established. We aimed to determine the association of 25(OH) vitamin D and VDR gene (BsmI and FokI) polymorphisms with T2DM and its accompanying atherosclerosis.
Patients and methods
This study enrolled 45 male patients with T2DM and manifested CVD who were admitted to the Department of Internal Medicine of Medical Research Institute Hospital, Alexandria University, Egypt, in addition to 45 healthy male volunteers. 25(OH) vitamin D was measured in all cases. Carotid intima-medial thickness was measured, in addition to analysis of VDR gene (BsmI and FokI) polymorphisms using PCR and restriction fragment length polymorphism for all studied participants.
Results
Significantly lower vitamin D levels were observed in the diabetic atherosclerotic group than controls. The minor allele f of the FokI polymorphism and the minor allele b of BsmI polymorphism were associated with a higher risk of coronary artery disease in patients with T2DM, with an odds ratio of 12.750 (=0.002) and 6.122 (1.202–30.078), respectively. FF genotype had significantly lower levels of total cholesterol and low-density lipoprotein cholesterol than Ff and ff genotypes (=0.01 and 0.04, respectively).
Conclusion
Presence of the f allele of FokI as well as the b allele of BsmI polymorphisms of the VDR gene could increase the risk of atherosclerosis in Egyptian patients with T2DM, through influencing lipid metabolism. Vitamin D deficiency might contribute to increased risk of atherosclerosis in T2DM independent of the variants of VDR gene.