A study published in Archives of Internal Medicine (14 January 2008, Volume 168, Issue 1) found that supplementation with vitamin D2 may reduce the number of falls in the elderly. The subjects of the study were 302 women averaging in age about 77 years, and living in an assisted living facility. They were divided into two groups, one group was given 1,000 IU of vitamin D2 per day and the other was given a placebo. Both the women in the placebo group and in the test group were tested and found to have lees than 24 ng/ml of vitamin D and a history of falling. Both groups received 1000 mg. per day of calcium citrate.

After one year of supplementation, the group receiving the vitamin D had significantly fewer falls. The risk of having at least one fall per year was 53% in the group receiving the supplementation and was 62.9% in the control group. In the winter, when vitamin D levels are lower, supplementation had a positive effect. When those who fell were grouped by the season of first fall or the number of falls they had, vitamin D supplementation reduced the risk of having the first fall in winter and spring ; with the vitamin D group having a 25.2% chance and the  control group  having a 35.8% chance of a first fall in the winter. Other research shows vitamin D to reduce pain and improve function in the elderly in general.