Research Review by Dr. Shawn Thistle©

Date:

June 2005

Study Title:

Fracture prevention with Vitamin D supplementation. A meta-analysis of randomized controlled trials

Authors:

Bischoff-Ferrari HA et al.

Publication Information:

JAMA 2005; 293(18): 2257-2264.

Summary:

Fractures are becoming an ever-increasing cause of disability and death among older people, particularly those with decreased bone density, or osteoporosis. Hip fractures increase exponentially such that 1 in 3 women and 1 in 6 men sustain a hip fracture by age 90. These fractures have severe health consequences, with 50% of people suffering permanent disability, and 10-20% dying within one year of the fracture. In addition to these personal consequences, fractures in the elderly pose a significant financial burden on the healthcare system.

Due to the high prevalence, severity, and cost of these fractures any preventive strategies that are effective and low in cost are needed. One such strategy that has been previously investigated is supplementation with Vitamin D. Results of studies investigating Vitamin D supplementation for fracture prevention have been contradictory.

The goal of this study was to perform a statistical meta-analysis (combining results of similar trials) to identify if supplementation with Vitamin D is effective in preventing hip and other non-vertebral fractures in the elderly, and which dose is most effective.

Studies included in the analysis had to be double-blind in nature, utilize oral Vitamin D supplementation, only include subjects 60 years or older, and have a minimum follow-up period of 1 year.

Seven randomized controlled trials met these criteria consisting of a total of 9820 subjects.

The primary outcome measure investigated was the relative risk of first hip or non-vertebral fracture in elderly patients taking a Vitamin D supplement with or without calcium versus those receiving placebo or calcium supplementation alone.

Pertinent Results:

  • Vitamin D dose of 700-800IU per day reduced the risk of hip fracture by 26%, and the risk of other non-vertebral fracture (ex. wrist) by 23% versus calcium or placebo
  • no significant benefit was noted in persons given a dose of 400IU per day
  • calcium was administered in addition to Vitamin D in all but one of the trials, making it difficult to identify an independent effect of Vitamin D

Conclusions & Practical Application:

This meta-analysis suggests that supplementation with 700-800IU per day of Vitamin D can reduce the risk of hip fracture by approximately 25%. Based on the combination of calcium and Vitamin D used in most studies, adding ~700mg of calcium per day may be necessary to obtain the greatest benefit.

Further, it seems that 400IU per day of Vitamin D, a dose commonly recommended by healthcare providers and supplement companies, is not adequate to provide this preventive effect.

As always, consult your healthcare professional before adding any dietary supplement to your plan.