Effect of annual intramuscular vitamin D on fracture risk in elderly men and women—a population-based, randomized, double-blind, placebo-controlled trial

Objectives. Low trauma fractures in older people incur enormous physical, social and economic costs. Previous research indicates that an annual intramuscular injection of vitamin D may reduce fracture rates in this group. This strategy requires validation in a population setting. Methods. Randomized, double-blind, placebo-controlled trial of 300 000 IU intramuscular (i.m.) vitamin D2 (ergocalciferol) injection or matching placebo every autumn over 3 years. 9440 people (4354 men and 5086 women) aged 75 yrs and over were recruited from general practice registers in Wessex, England. Primary outcome measure was all non-vertebral fracture. Secondary outcomes were hip and wrist fractures, and all falls. Results. 585 subjects had incident non-spine fractures (hip 110, wrist 116, ankle 37). Hazard ratios (HRs) for fracture in the vitamin D group were: 1.09 [95% confidence interval (CI) 0.93–1.28, P = 0.29] for any first fracture, 1.49 (95% CI 1.02–2.18, P = 0.04) for hip and 1.22 (95% CI 0.85–1.76, P = 0.28) for wrist. There was no effect on falls: HR 0.98 (0.93–1.04). No protective effect was observed in any subgroup when the cohort was stratified by sex, age, previous fracture or mobility. Conclusions. An annual i.m. injection of 300 000 IU vitamin D2 is not effective in preventing non-vertebral fractures among elderly men and women resident in the general population