Effect of Vitamin D Supplementation on Muscle Strength, Gait and Balance in Older Adults: A Systematic Review and Meta-Analysis

OBJECTIVES: To systematically review and quantitatively synthesize the effect of vitamin D supplementation on muscle strength, gait, and balance in older adults. DESIGN: Systematic review and meta-analysis. SETTING: MEDLINE, EMBASE, Cochrane Library, bibliographies of selected articles, and previous systematic reviews were searched between January 1980 and November 2010 for eligible articles. PARTICIPANTS: 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. MEASUREMENTS: Data were independently extracted, and study quality was evaluated. Meta-analysis using a fixed-effects model was performed and the I 2 statistic was used to assess heterogeneity. RESULTS: 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, P =.04, I 2 = 0%) for reduced postural sway, -0.19 (95% CI = -0.35 to -0.02, P =.03, I 2 = 0%) for decreased time to complete the Timed Up and Go Test, and 0.05 (95% CI = -0.11 to 0.20, P =.04, I 2 = 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. CONCLUSION: Supplemental vitamin D 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. J Am Geriatr Soc 59: 2291-2300, 2011.