RESUMEN
Background: Osteoporotic hip fractures are devastating events in older women. There is a genetic modulation of bone phenotypic parameters including bone density (BMD) and bone fragility fractures. Vitamin D receptor (VDR) gene polymorphisms explain a small part of the genetic influence on BMD, whereas their effect on fractures remains uncertain. Aim: To examine the contributions of VDR genotypes to the susceptibility to hip fracture in elderly Chilean women. Patients and methods: We recruited 126 women (67 with fractures and 59 without) from Bio-Bio Region, Chile, aged 65 to 94 years. Genotyping for Bsm-l, Apa-1, Taq-1 and Fok-1 VDR polymorphisms was performed using polymerase chain reaction methods. All hip fractures were confirmed by X-ray. Results: The alíele frequencies were 0.49 for B, 0.57 for A, 0.60 for T and 0.65 for F in the Bsm-l, Apa-1, Taq-1 and Fok-1 polymorphisms respectively. The prevalence of these VDR gene polymorphisms in women with fractures were 16 percent BB, 69 percent Bb, 15 percent bb for Bsm-l; 30 percent AA, 46 percent Aa, 14 percent aa for Apa-1; 17 percent TT, 34 Tt, 8 percent tt for Taq-1 and 43 percentFF, 41 percent Ff, 16 percent ff for Fok-1. All VDR genotype frequencies did not differ from Hardy- Weinberg expectations. Alíele or genotype frequencies did not differ between women with or without fractures. These results did not change when analysis was adjusted by age weight, height or gynecologic history. Conclusions: The genotype frequencies of the VDR polymorphisms are in accordance with the frequencies of other Hispanic and Caucasian populations. Our results suggest that VDR polymorphisms are not associated with the risk of hip fracture in older women of this Region of Southern Chile.