Vitamin D receptor alleles and bone mineral density in a normal premenopausal Brazilian female population

RESUMO

Studies on the association between vitamin D receptor (VDR) polymorphism and bone mineral density (BMD) in different populations have produced conflicting results probably due to ethnic differences in the populations studied. The Brazilian population is characterized by a very broad genetic background and a high degree of miscegenation. Of an initial group of 164, we studied 127 women from the city of Spo Paulo, aged 20 to 47 years (median, 31 years), with normal menses, a normal diet and no history of diseases or use of any medication that could alter BMD. VDR genotype was assessed by PCR amplification followed by BsmI digestion of DNA isolated from peripheral leukocytes. BMD was measured using dual energy X-ray absorpitometry (Lunar DPX) at the lumbar site (L2-L4) and femoral neck. Most of the women (77.6 per cent) were considered to be of predominantly European ancestry (20.6 per cent of them reported also native American ancestry), 12.8 per cent were of African-Brazilian ancestry and 9.6 per cent of Asian ancestry, 41.0 per cent (52) were classified as bb, 48.8 per cent (62) as Bb and 10.2 per cent (13) as BB. The BB, Bb and bb groups did not differ in age, height, weight, body mass index or age at menarche, Lumbar spine BMD was significantly higher in the bb group (1.22 + 0.16 g/cm2) than in the BB group (1.08 + 0.14; P<0.05), and the Bb group presented an intermediate value (1.17 + 0.15). Femoral neck BMD was higher in the bb group (0.99 + 0.11 g/cm2) compared to Bb (0.93 + 0.12) and BB (0.90 + 0.09) (P<0.05). These data indicate that there is a significant correlation between the VDR BsmI genotype and BMD in healthy Brazilian premenopausal females.