Endocrine Abstracts

Our aims were to follow the longitudinal changes after 5-year in femoral neck (FN), femoral trochanter (FT), L2, L3, L4 and L2–L4 bone mineral density (BMD) in Spanish postmenopausal women and to study whether the polymorphism BsmI in the vitamin D receptor (VDR) may influence these results.

We conducted a 5-year prospective study of BMD and its change in 174 women, aged 43–78 years. BMD was measured by densitometry. The women were members of the Caceres Reference Database for the Diagnosis of Osteoporosis (CAFOR), a population-based longitudinal study of BMD. Changes were analysed by Wilcoxon test. We also examined the effect of adjustments for dietary and anthropometric factors on these associations. After the 5-year period significant changes were observed in L3, L4, L2–L4, FN and FT (P<0.001 in all cases). No significant changes were observed in L2 (P=0.598). Before adjustments, in women homozygous for the b allele (genotype (bb) n=25) no significant changes were observed (P>0.05 in all cases). Women heterozygous (genotype (Bb) n=73) had less FT BMD (P<0.001), L4 (P<0.001) and L2–L4 (P=0.010) over time; no changes were observed over the 5-year period in Bb women in FN, L2 and L3 BMD. In women homozygous for the B allele (n=76) significant loss in BMD was observed in FN (P=0.010) and FT (P<0.001) BMD as well as in L4 (P<0.001) and L2–L4 (P=0.012) BMD after the 5-year period. No changes were observed in L2 and L3 BMD (P>0.05 in both cases). Upon adjustment for dietary and anthropometric factors no further statistically significant associations to BsmI polymorphism were found.

Our results reveal that to correctly address the association between bone loss and VDR polymorphism BsmI in small samples, it is necessary to consider the variations in dietary and anthropometric factors.