title: Vitamin D Receptor Gene Polymorphisms, Metabolic Syndrome, and Type 2 Diabetes in Iranian Subjects: No Association with Observed SNPs.
abstract: OBJECTIVE
  This study aimed to investigate the associations between metabolic syndrome and type 2 diabetes and the presence of single nucleotide polymorphism of the vitamin D receptor gene in Iranian subjects with type 2 diabetes.
  
  
  METHODS
  Overall, 730 Iranian subjects (372 patients and 358 controls) were enrolled in this case-control study. Single nucleotide polymorphisms of the vitamin D receptor gene (FokI, BsmI, ApaI, and TaqI) were genotyped using the restriction fragment length polymorphism method. The statistical difference in genotype distribution among the groups was assessed by χ2 test. Logistic regression was performed to calculate odds ratios for the association of the genotype frequencies in different groups with the risk of metabolic syndrome and type 2 diabetes.
  
  
  RESULTS
  The most common genotypes for BsmI, ApaI, TaqI, and FokI were Bb, Aa, TT, and FF, respectively. Adjusted χ2 test revealed that there was no difference between the groups in the genotypes frequencies of 4 vitamin D receptor polymorphisms in type 2 diabetes subjects. On the other hand, type 2 diabetes subjects with Tt genotype presented a signifi cantly higher fasting blood glucose than those with TT and tt genotypes in TaqI polymorphisms (p = 0.009). Logistic regression showed no association between metabolic syndrome risk and vitamin D receptor genotypes.
  
  
  CONCLUSIONS
  We found no evidence for the association between vitamin D receptor gene polymorphisms and the risk for type 2 diabetes and metabolic syndrome in Iranian subjects. Further examinations using genome-wide association in large prospective cohort studies are warranted.
authors.affiliation: 1Department of Community Nutrition, School of Nutritional Sciences and Dietetics, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Sakineh
authors.initials: S
authors.lastname: Shab-Bidar
authors.affiliation: 2Laboratory of Nutrition Research, National Nutrition and Food Technology Research Institute and Faculty of Nutrition and Food Technology Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Tirang R
authors.initials: TR
authors.lastname: Neyestani
authors.affiliation: 1Department of Community Nutrition, School of Nutritional Sciences and Dietetics, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Abolghassem
authors.initials: A
authors.lastname: Djazayery
keywords: Vitamin D recepetor; gene; metabolic syndrom; polymorphism; type 2 diabetes