Efficacy of vitamin D3 supplementation in preventing fractures in elderly women: A meta-analysis

Background: The efficacy of vitamin D-3 in preventing fractures and falls has been explored in a number of clinical trials. However, recent evidence revealed new questions about the adequate doses of vitamin D-3 supplementation and its efficacy in fracture prevention independent of calcium supplements for various types of fractures. Objective: To conduct a meta-analysis to estimate the effectiveness of 800 IU daily vitamin D-3 supplementation for increasing bone mineral density (BMD) and preventing fractures in postmenopausal women. Methods: Medline and EMBASE were searched for controlled trials comparing the effectiveness of cholecalciferol (vitamin D-3) against placebo with or without background calcium supplementation in the treatment of postmenopausal women. Results: Eight controlled trials evaluating the effect of vitamin D-3 supplementation with or without calcium were assessed. Of 12 658 women included in a Bayesian meta-analysis, 6089 received vitamin D-3 (with or without calcium) and 6569 received placebo (with or without calcium). Compared to placebo, vitamin D3 with calcium supplementation showed beneficial effects on the incidence of non-vertebral (odds ratio [OR] 0.77, 95% credibility limit [CL] 0.6-0.93) and hip (OR 0.70, 95% CL 0.53-0.90) fractures, while the effects on non-vertebral-non-hip fractures (OR 0.84, 95% CL 0.67-1.04) % point increase) were associated with more uncertainty. Vitamin D-3 supplementation showed a 70% probability of being a better treatment than placebo for the prevention of non-vertebral fractures, hip fractures, and non-vertebral, non-hip fractures. Compared to calcium supplementation, vitamin D-3 plus calcium reduced non-vertebral fractures (OR 0.68, 95% CL 0.43-1.01) and non-vertebral, non-hip fractures (OR 0.64, 95% CL 0.38-0.99), but did not reduce hip fractures (OR 1.03, 95% CL 0.39-2.25). Key limitations to this analysis include a small number of studies and heterogeneity in the study populations. Conclusions: This meta-analysis supports the use of vitamin D3 of 800 IU daily to reduce the incidence of osteoporotic non-vertebral, hip, and non-vertebral-non-hip fractures in elderly women. Vitamin D-3 with calcium appears to achieve benefits above those attained with calcium supplementation alone for non-vertebral and non-vertebral-non-hip fractures.