Vitamin D Receptor Alleles, Bone Mineral Density and Turnover in Postmenopausal Osteoporotic and Healthy Women

Abstract

OBJECTIVE: Vitamin D receptor (VDR) gene polymorphisms and bone metabolic markers were investigated as potential genetic markers for osteoporosis in postmenopausal Turkish women. The relationship between their VDR gene polymorphisms and bone states was determined. MATERIALS AND METHODS: Restriction fragment length polymorphisms at the VDR gene locus (i.e., for BsmI, ApaI, and TaqI) was investigated in 75 postmenopausal osteoporotic (53.16 +/- 1.31 years) and 66 healthy (52.62 +/- 1.69 years) Turkish women and the genotypes were related to bone mineral density (BMD) at femoral neck (FN), lumbar spine (L1-4), trochanter, Ward's triangle (Ward's) and metabolic parameters of bone turnover. RESULTS: In osteoporotic women, TaqI genotype-related differences of the VDR gene were found to be significant at all BMD sites; TT genotype had higher L1-4 BMD values than Tt and tt (p < 0.05); tt genotype had significantly lower BMD at FN (p < 0.05), trochanter (p < 0.01), and Ward's (p < 0.05) compared to TT genotype. The tt genotype was found to be associated with higher (p < 0.05) serum osteocalcin levels compared to Tt and TT genotypes in the osteoporotic women, whereas no such association was found for the healthy women. CONCLUSION: Our data showed an association between VDR TaqI genotype and BMD at the FN, L1-4, trochanter and Ward's triangle in nonobese postmenopausal osteoporotic women. Thus the VDR gene Taql polymorphism modulates differences in BMD in the postmenopausal osteoporotic women.