To the Editor The article by Uusi-Rasi and colleagues1 raises important considerations in the study design of randomized clinical trials on the effect of vitamin D on falling. It is clear from many randomized clinical trials that the role of vitamin D supplementation on falling—if it has a role—is likely to be found in subsets of the falling population.2 It is unfortunate that the study design did not take advantage of previous study findings.
Prince RL, Lewis J, Ebeling PR. Study Design for Vitamin D Randomized Clinical Trials. JAMA Intern Med. 2015;175(10):1720. doi:10.1001/jamainternmed.2015.3765