The results of a three year randomized controlled trial published in the February 27 2006 issue of the American Medical Association journal Archives of Internal Medicine found that long-term supplementation with vitamin D and calcium reduces the risk of falls in older women. The combination did not appear to influence falls in older men.

Heicke A. Bischoff-Ferrari, MD, of University Hospital Zurich, Switzerland and colleagues at Harvard School of Public Health and Tufts University analyzed data from 199 men and 246 women aged 65 and older enrolled in a study designed to show the effect of vitamin D and calcium on bone density. Participants received 500 milligrams calcium citrate malate with 700 international units vitamin D in the form of cholecalciferol, or a placebo for three years. Three hundred-eighteen participants completed their course of treatment.

At the study's conclusion, 45 percent of the men and 55 percent of the women reported one or more falls. The vitamin D and calcium combination was found to reduce the odds of falling among active women by 46 percent compared to those who received the placebo. Among women classified as less physically active, vitamin D and calcium supplementation was associated with a 65 percent reduction in falls, and for women who completed treatment throughout the three year follow-up, the risk was further reduced. For men enrolled in the study, the number reporting at least one fall in the treatment and placebo groups was almost the same. Activity level among men did not appear to influence responsiveness to treatment.

"Our results have clinical significance," the authors conclude. "We show a significant reduction in the odds of falling in ambulatory older women with a very inexpensive, well-tolerated, and simple supplementation with cholecalciferol-calcium."