Effect of Vitamin <scp>D</scp> Supplementation on Muscle Strength, Gait and Balance in Older Adults: A Systematic Review and Meta‐Analysis

<jats:sec> <jats:title>Objectives</jats:title> <jats:p> To systematically review and quantitatively synthesize the effect of vitamin <jats:styled-content style="fixed-case">D</jats:styled-content> supplementation on muscle strength, gait, and balance in older adults. </jats:p> </jats:sec> <jats:sec> <jats:title>Design</jats:title> <jats:p>Systematic review and meta‐analysis.</jats:p> </jats:sec> <jats:sec> <jats:title>Setting</jats:title> <jats:p>MEDLINE, EMBASE, Cochrane Library, bibliographies of selected articles, and previous systematic reviews were searched between January 1980 and November 2010 for eligible articles.</jats:p> </jats:sec> <jats:sec> <jats:title>Participants</jats:title> <jats:p>Older adults (≥60) participating in randomized controlled trials of the effect of supplemental vitamin D without an exercise intervention on muscle strength, gait, and balance.</jats:p> </jats:sec> <jats:sec> <jats:title>Measurements</jats:title> <jats:p> Data were independently extracted, and study quality was evaluated. Meta‐analysis using a fixed‐effects model was performed and the <jats:italic>I</jats:italic> <jats:sup>2</jats:sup> statistic was used to assess heterogeneity. </jats:p> </jats:sec> <jats:sec> <jats:title>Results</jats:title> <jats:p> Of 714 potentially relevant articles, 13 met the inclusion criteria. In the pooled analysis, vitamin D supplementation yielded a standardized mean difference of −0.20 (95% confidence interval (CI) = −0.39 to −0.01, <jats:italic>P</jats:italic>  = .04, <jats:italic>I</jats:italic> <jats:sup>2</jats:sup>  = 0%) for reduced postural sway, −0.19 (95% CI = −0.35 to −0.02, <jats:italic>P</jats:italic>  = .03, <jats:italic>I</jats:italic> <jats:sup>2</jats:sup>  = 0%) for decreased time to complete the Timed Up and Go Test, and 0.05 (95% CI = −0.11 to 0.20, <jats:italic>P</jats:italic>  = .04, <jats:italic>I</jats:italic> <jats:sup>2</jats:sup>  = 0%) for lower extremity strength gain. Regarding dosing frequency regimen, only one study demonstrated a beneficial effect on balance with a single large dose. All studies with daily doses of 800 IU or more demonstrated beneficial effects on balance and muscle strength. </jats:p> </jats:sec> <jats:sec> <jats:title>Conclusion</jats:title> <jats:p> Supplemental vitamin <jats:styled-content style="fixed-case">D</jats:styled-content> with daily doses of 800 to 1,000 IU consistently demonstrated beneficial effects on strength and balance. An effect on gait was not demonstrated, although further evaluation is recommended. </jats:p> </jats:sec>