The Associations Between Vitamin D Receptor BsmI and ApaI Polymorphisms and Obesity in Korean Patients with Type 2 Diabetes Mellitus.

Background: Vitamin D receptor ( VDR ) polymorphisms are associated with osteoporosis, diabetes, immunological diseases, and cancers. However, the association of obesity with VDR polymorphisms has shown inconsistent results, and perhaps it depends upon the characteristics of a population. Therefore, we evaluated the association between BsmI (rs1544410) and ApaI (rs7975232) polymorphisms of VDR and obesity in Korean patients with type 2 diabetes mellitus (T2DM).

Methods: A total of 506 patients with T2DM participated in the study. Polymerase chain reaction-restriction fragment length polymorphism was used to analyze BsmI and ApaI polymorphisms; the genotypes were presented as BB, Bb, or bb for BsmI and AA, Aa, or aa for ApaI. Obesity was defined using the body mass index (BMI) with a cutoff level of 25 kg/m2 .

Results: The prevalence of obesity was higher in patients with the bb genotype than in those with BB or Bb genotypes (48.4% vs 33.9%, P = 0.031). The mean BMI was 25.2 ± 3.5 kg/m2 in patients with bb genotype and 24.1 ± 3.1 kg/m2 in patients with BB or Bb genotypes. Patients with Aa or aa genotypes showed a higher prevalence of obesity than patients with AA genotype (47.6% vs 26.1%, P = 0.043). Glycemic control parameters and lipid profiles did not show significant differences with either polymorphism.

Conclusion: To our knowledge, this is the first study to assess the association between VDR polymorphisms and obesity in Korean patients with T2DM. Further studies in larger populations and multiethnic cohorts are needed to validate our findings.