The role of vitamin D in fracture risk remains controversial. A recent meta-analysis demonstrated no reduction in fracture risk in those taking regular vitamin D supplementation, whilst a meta-analysis of randomised controlled trials suggested that annual vitamin D supplementation was associated with an increased hip fracture risk.

To evaluate the role of vitamin D supplementation in fracture risk, Waterhouse and colleagues undertook a population-based, double-blind, randomised, placebo-controlled trial of oral vitamin D3 supplementation (60,000IU per month) in adults aged 60–84 years living in Australia. In total, 21,315 participants were randomised to vitamin D or placebo, and participants were followed for up to five years. The main outcome assessed was total fractures.

In this analysis, 20,326 participants were included (vitamin D, n=10,154; placebo, n=10,172). Over a median follow-up period of 5.1 years, 5.6% of participants in the vitamin D group and 5.9% of participants in the placebo group had one or more fractures. Monthly vitamin D supplementation did not have an effect on overall fracture risk (HR 0.94; 95% CI 0.84–1.06). However, the HR for total fractures reduced with increasing follow-up time.

This study demonstrates that monthly supplementation with vitamin D was not associated with increased fracture risk. Whilst there was a suggestion that longer term supplementation may reduce fracture incidence, further research is required.

Read the full article in Lancet Diabetes & Endocrinology 11 324–332