Association of BsmI vitamin-D receptor gene polymorphism with combined bone mass in spine and proximal femur in Icelandic women

Abstract

OBJECTIVE: To evaluate whether there is an association between BsmI-vitamin-D receptor (VDR) gene polymorphism and combined bone mass in the spine and proximal femur in a group of adult Icelandic women with high and low bone mineral density (BMD). DESIGN: Comparison of distribution of VDR genotypes (BB, Bb and bb) and allele frequency (B and b) in two groups of women: a group with 'strong bones' with high BMD in both the spine and proximal femur (> 1 standard deviation [SD]) above the age-matched mean (n = 35) and a group with 'weak bones' with BMD > 1.5 SD below the age-matched mean at both sites using dual energy X-ray absorptiometry. SETTING: Iceland, a population with a mean calcium intake > 1000 mg day-1. The calcium intake in the study group was however not evaluated. SUBJECTS: Eighty-three Icelandic women, aged 22-65, free of diseases affecting bone and not taking drugs affecting calcium or bone metabolism, recruited from women undergoing bone densitometry at the Reykjavik Hospital. MAIN OUTCOME MEASURES: Frequency of VDR genotypes and alleles in the two groups. RESULTS: The distribution of VDR genotypes was significantly different in the two groups (P < 0.01); the b allele frequency was 70% in the group with high BMD compared to 48.5% in the group with low BMD. CONCLUSIONS: In this selected group of adult Icelandic women the b allele in the vitamin-D receptor gene seems to be associated with high bone mass in the spine and proximal femur.