More Vitamin D May Be Key to Preventing Fractures

June Chen, MD

The effectiveness of vitamin D supplements in preventing bone fractures has been controversial. Investigators have tried to clear up the controversy by looking at data from multiple clinical trials. In the March 23, 2009 issue of the Archives of Internal Medicine, they report that the efficacy of fracture prevention with vitamin D is dependent on the dose.

Researchers from the University of Zurich in Switzerland and their colleagues performed a meta-analysis of 12 double-blind randomized controlled trials (RCTs) for nonvertebral (in other words, not related to the spine) fractures and 8 RCTs for hip fractures. These trials all compared the use of oral vitamin D supplements, with or without calcium, versus the use of calcium or placebo. The researchers found that the anti-fracture efficacy of vitamin D increased significantly with a higher dose and a resulting higher level of vitamin D in the blood. A vitamin D dose of more than 400 IU per day reduced nonvertebral fractures in both community-dwelling individuals and institutionalized older individuals.

In addition, the researchers found that the anti-fracture effect of vitamin D was independent of additional calcium supplementation. Based on their findings, the researchers concluded that a higher dose of vitamin D should reduce fractures by at least 20% for adults aged 65 years or older.

Source
Arch Intern Med. 2009;169:551-561.