Polymorphisms of the VDR, ER and COLIA1 genes and osteoporotic hip fracture in elderly postmenopausal women

In view of the reported associations between osteoporosis and polymorphisms of the vitamin D receptor (VDR), collagen I alpha 1 (COLIA1) and estrogen receptor (ER) genes, an association study was performed between VDR, COLIA1 , and ER genotypes and bone mineral density, biochemical markers of bone tu rnover and hip fracture occurrence in Belgian older postmenopausal women. T he gene polymorphisms were evaluated by restriction fragment length polymor phism analyses, using the restriction enzymes BsmI (VDR), AccB71 (COLIA1), and PvuII and XbaI (ER), respectively. As expected, bone mineral density an d biochemical analyses demonstrated significant differences between hip fra cture patients and elderly controls. However, no significant differences in genotype distributions or allele frequencies were observed between the cas es (n = 135, age 78 +/- 9 years) and controls (n = 239, age 76 +/- 4 years) for any of the gene polymorphisms. Stratification of both study population s according to VDR, COLIA1 or ER genotype did not reveal any statistically significant difference in bone density or bone turnover between subgroups w ith different genotypes. In conclusion, despite its limited statistical pow er the outcome of this study does not support the hypothesis of a major con tribution of the VDR, COLIA1 or ER polymorphisms to explain variations in b one mineral density or bone turnover, or to identify elderly women at risk of osteoporotic hip fracture.