Association between FokI Vitamin D Receptor Gene Polymorphism and Visceral Obesity in Patients with Type 2 Diabetes: A Single-Blinded Randomised Clinical Trial

Role of genetic variants on the effect of vitamin D on adiposity measures is still unclear. This study aimed to investigate the effect of vitamin D on visceral adiposity using intake of vitamin D fortified doogh.

This was a single-blinded randomised clinical trial which seventy type 2 diabetic Iranian subjects were randomly allocated to two groups of receiving plain Doogh (PD; n 32, containing 170 mg Ca and no vitamin D/250 ml) or vitamin D3-fortified Doogh (FD; n 38, containing 170 mg Ca and 12•5 μg/250 ml) twice a day for 3 months. Serum 25-hydroxyvitamin D (25(OH)D, anthropometric measures, body composition, glycaemic status and visceral obesity indicators assessed twice before and after the intervention. Genotyping was conducted for FokI single nucleotide polymorphisms (SNPs) of the VDR gene by polymerase chain reaction.

Serum 25(OH)D (P<0.001) was increased in FD compared to PD and waist circumference (P= 0.022), fat mass (P<0.001), visceral adipose tissue (P<0.001), and trunk fat (P<0.001) were decreased after 3-month intervention. Analysis of FOK-1 genotyping was showed significant change for 25(OH)D (P=0.03), FSG (P=0.036), HbA1c (P=0.003), waist circumference (P=0.045), waist: hip ratio (P=0.04), fat mass (P=0.016), visceral adipose tissue (P=0.024), and Truncal fat (P=0.004) after Tukey’s post hoc analysis.

In conclusion, FD compared to PD could increase serum 25(OH)D and improve glyceamic, anthropometric, and visceral obesity indicators. Moreover, significant differences was seen between FOK-1 (FF, Ff, and ff) genotypic groups for 25(OH)D, FSG, HbA1c, waist circumference, waist: hip ratio, fat mass, visceral adipose tissue, and Truncal fat