Ten RCTs in total were included. Of these, 5 RCTs met the inclusion criteria and were included in the main analysis (1,237 participants); the 5 RCTs that did not meet the inclusion criteria were included in the sensitivity analysis. A total of 10,0001 participants were included in the secondary analyses.
Of the 5 RCTs included in the main analyses, four reported the method of randomisation and allocation concealment, and the results were analysed on an intention-to-treat basis. Three were blinded to treatment allocation. The reasons for drop-out were balanced between the treatment and control groups, and ranged from 7 to 28% across the trials.
There was a statistically significant decrease of 22% in the risk of having a fall in older people taking vitamin D in comparison with participants receiving calcium or placebo (5 RCTs) The corrected OR was 0.78 (95% CI: 0.64, 0.92), with an associated NNT of 15 (95% CI: 8, 53). The authors reported that there was no statistically significant heterogeneity between these studies.
When the additional 5 studies that did not meet the inclusion criteria were included in the analysis, there was a statistically significant decrease of 13% in the risk of having a fall in older people taking vitamin D in comparison with the control. The corrected OR was 0.87 (95% CI: 0.80, 0.96).
The results of several subgroup analyses were reported in the review. The authors reported that there was no evidence of publication bias.