1. Home>
2. Specialties>
3. General Medicine>
4. Summary and Comment

Does Vitamin D Supplementation Prevent Fractures?

Previous studies have yielded conflicting results on the effectiveness of oral vitamin D supplementation in preventing fractures in older patients. These investigators conducted a meta-analysis of seven randomized controlled trials of vitamin D supplementation (with or without calcium) versus either calcium alone or placebo. The trials included 9820 subjects (mean age, 79; 68% women) who were followed for nonvertebral fractures for 18 to 60 months; 9294 subjects were assessed specifically for hip fractures.

Low-dose vitamin D (400 IU daily) had no effect on risk for hip fractures, but high-dose supplementation (700–800 IU daily) was associated with a 26% relative risk reduction and a 2% absolute risk reduction (number needed to treat [NNT], 45). For all nonvertebral fractures, high-dose supplementation was associated with a 23% relative risk reduction and a 4% absolute risk reduction (NNT, 27). Again, low-dose supplementation provided no benefit.

Interestingly, a new clinical trial is at odds with this meta-analysis. Investigators in the U.K. conducted a randomized trial of 3314 community-dwelling older women (age, 70) who reported at least one of the following risk factors: previous fracture, low body weight (<58 kg), fair or poor health, cigarette use, or maternal history of fracture. The intervention group received daily supplements of calcium (1000 mg) and cholecalciferol (vitamin D₃; 800 IU), whereas the control group received printed information. Fractures were self-reported and confirmed by physicians. During a median follow-up of 24 months, the incidence of all fractures was similar in the two groups (about 4.5%).

Comment: Important differences between trials — in terms of patient populations, vitamin D doses, enrollees’ initial vitamin D status, and calcium intake — probably have led to conflicting results among clinical trials. However, the overall body of evidence suggests that vitamin D plus calcium offers benefit to some patients. At the time of publication, the full text of the BMJ article was available free of charge.

— Thomas L. Schwenk, MD, and Keith I. Marton, MD

Published in Journal Watch General Medicine June 3, 2005

Citation(s):

Bischoff-Ferrari HA et al. Fracture prevention with vitamin D supplementation: A meta-analysis of randomized controlled trials. JAMA 2005 May 11; 293:2257-64.

• Original article (Subscription may be required)
• Medline abstract (Free)

Porthouse J et al. Randomised controlled trial of calcium and supplementation with cholecalciferol (vitamin D₃) for prevention of fractures in primary care. BMJ 2005 Apr 30; 330:1003-5.

• Original article (Subscription may be required)
• Medline abstract (Free)