Effects of Vitamin D on Depression, Cognitive Function, and Physical Function in Elderly Individuals Living Alone

Background: We examined the effects of vitamin D on depression, cognitive function, and physical function in elderly, community-dwelling individuals living alone. Methods: In this non-equivalent, control-group experimental study, participants with serum vitamin D levels ＜ 20 ng/mL and who lived alone were enrolled from eight senior centers in S city, Gyeonggi-do. Forty-six individuals were assigned to the experimental group and forty-eight to the control group. Vitamin D supplements and exercise programs were prescribed to the experimental group; the control group was prescribed only exercise programs. Treatment duration was 12 weeks. Depression, cognitive function, physical function (muscle mass, grip strength, static balance, time to walk a standard course, and arm flexibility), vitamin D and calcium levels were measured before and after treatment. Collected data were analyzed using chi-squared test, Fisher's exact test, t-test and multivariate logistic regression analysis. Results: Depression levels and cognitive function improved in both groups, the difference was not significant. Vitamin D levels (p ＜ 0.001), muscle mass (p = 0.014), and time to walk a standard course (p = 0.012) improved in the experimental group. Conclusion: Vitamin D supplementation for 12 weeks in vitamin-D deficient elderly individuals living alone was associated with improved vitamin D levels, muscle mass, and time to walk a standard course.