Author/Authors :
Montazeri-Najafabady ، Nima Endocrinology and Metabolism Research Center, Nemazee Hospital - Shiraz University of Medical Sciences , Dabbaghmanesh ، Mohammad Hossein Endocrinology and Metabolism Research Center, Nemazee Hospital - Shiraz University of Medical Sciences , Mohammadian Amiri ، Rajee Endocrinology and Metabolism Research Center, Nemazee Hospital - Shiraz University of Medical Sciences , Akbarzadeh ، Mahdi Cellular and Molecular Research Center, Research Institute for Endocrine Sciences - Shahid Beheshti University of Medical Sciences
Abstract :
Background The vitamin D receptor (VDR) gene variants are known as the main risk factor for low bone mass. Objectives In this study, the association of vitamin D receptor genetic variants, BsmI (rs1544410) and FokI (rs2228570), with bone mass in Iranian children and adolescents, was evaluated. Methods The study population comprised of children and adolescents aged between 9 to 18 years (FokI: 123 boys and 120 girls, BsmI: 108 boys and 110 girls). Vitamin D, calcium, phosphorus, total cholesterol (TC), High-density lipoprotein-cholesterol (HDL-C) and triglyceride (TG) concentrations were assayed. Bone mineral density and body composition parameters were measured by the Hologic system DXA. BMD Z-score ≤ -2 was considered as low bone density for chronologic age. PCR-restriction fragment length polymorphism was done for genotyping of BsmI and FokI polymorphisms. The association between VDR variants and bone mineral density was investigated using logistic regression analysis. Results No significant differences in body composition and biochemical parameters were detected among the evaluated VDR genotypes. For VDR BsmI, the mean values for Z-score of the lumbar spine, neck, inter and total femur was greater in the bb genotype compared to BB and Bb genotypes. Logistic regression analysis revealed a significant association between femoral neck Z-score and VDR BsmI genotypes in an additive genetic model (unadjusted model (P = 0.035; Bb vs. bb), model 1 (adjusted for age and sex, P = 0.021; Bb vs. bb), model 2 (adjusted for age, sex and BMI, P = 0.013; Bb vs. bb) and model 3 (adjusted for age, sex, BMI and puberty, P = 0.011; Bb vs. bb, P = 0.049; BB vs. bb)) and dominant genetic model ((unadjusted model, P = 0.033; BB+Bb vs. bb), model 1 (adjusted for age and sex, P = 0.023; BB+Bb vs. bb), model 2 (adjusted for age, sex and BMI, P = 0.012; BB+Bb vs. bb and model 3 (adjusted for age, sex, BMI and puberty, P = 0.012; BB+Bb vs. bb)). Conclusions This investigation indicated that VDR BsmI polymorphism may be associated with BMD Z-score of the femoral neck but not the lumbar spine, in Iranian children and adolescents.
Keywords :
Vitamin D Receptor , RFLP , Bone Mineral Density , Children
