Preventing fractures among older people living in institutional care: a pragmatic randomised double blind placebo controlled trial of vitamin D supplementation

Introduction Osteoporotic fractures in older people are a major and increasing public health problem. We examined the effect of vitamin D supplementation on fracture rate in people living in sheltered accommodation. Methods In a pragmatic double blind randomised controlled trial of 3 years duration, we examined 3,440 people (2,624 women and 816 men) living in residential or care home. We used four-monthly oral supplementation using 100,000 IU vitamin D2 (ergocalciferol). As a main outcome measure, we used the incidence of first fracture using an intention to treat analysis. This was a multicentre study in 314 care homes or sheltered accommodation complexes in South Wales, UK. Results The vitamin D and placebo groups had similar baseline characteristics. In intention-to-treat analysis, 205 first fractures occurred in the intervention group during a total of 2,846 person years of follow-up (7 fractures per 100 people per year of follow-up), with 218 first fractures in the control group over 2,860 person years of follow-up. The hazard ratio of 0.95 (95% confidence interval 0.79–1.15) for intervention compared to control was not statistically significant. Conclusion Supplementation with four-monthly 100,000 IU of oral vitamin D2 is not sufficient to affect fracture incidence among older people living in institutional care