BsmI vitamin D receptor genotypes influence the efficacy of antiresorptive treatments in postmenopausal osteoporotic women. A 1-year multicenter, randomized and controlled trial

Vitamin D receptor (VDR) gene polymorphisms could be considered one of the factors influencing the efficacy of the anti-osteoporotic treatments. In this multicenter, prospective, randomized and controlled trial we evaluated whether BsmI vitamin D receptor (VDR) genotypes influence the efficacy of antiresorptive treatment regimes (administered alone or in combination) in postmenopausal osteoporotic women. Using restriction endonuclease, we identified the BsmI VDR polymorphism in 1,100 postmenopausal women with osteoporosis. The women were randomized, taking account of genotype, into five treatment groups: (1) alendronate (Aln, 10 mg/day) plus raloxifene (Rlx, 60 mg/day); (2) Aln plus hormone replacement therapy (HRT, 0.625 mg/day conjugated equine estrogens plus 2.5 mg/day medroxyprogesterone acetate); (3) Aln alone; (4) HRT alone; and (5) Rlx alone. Lumbar-spine bone mineral density (BMD) and bone turnover markers were measured at study entry and after 1 year of treatment. Using the general linear model (GLM) repeated-measures procedure, the means of BMD and bone turnover markers significantly differed from baseline after a period of treatment. In particular, the mean change from baseline for BMD was -0.034 (95% confidence interval [CI]: -0.037 to -0.031, P