12/22/2009 - Articles

Vitamin D Strengthens Muscles and Prevents Falls

By: Robert W. Griffith, MD


It seems that vitamin D has a specific effect in the elderly - improving muscle strength, thus improving their chances of avoiding falls. This is in addition to its role in improving bone mineral density.

Vitamin D Strengthens Muscles and Prevents Falls

Summarized by Robert W. Griffith, MD
August 20, 2004


Falls are the largest single cause of injury-related deaths in elderly people, and lead to 40% of all nursing home admissions. Avoiding osteoporosis is an important step in reducing the risk the most serious consequence of a fall - a fractured bone. And it was thought that vitamin D, along with adequate calcium intake, would prevent osteoporosis, and hence fractures following falls. But recently it's been recognized that vitamin D may directly improve muscle strength, and thus help prevent a fall in the first place.

Many clinical studies have been published concerning the role of vitamin D in fall prevention. Now a group of experts has examined these publications, conducting what is called a 'meta-analysis' - this is an analysis of combined results from a number of suitable separate studies. Here's a summary of their conclusions.

What was done

Thirty-eight published randomized (subjects were allocated at random to receive one of at least two types of treatment), controlled (the active treatment was compared with an inactive - placebo - treatment, or another active treatment), clinical trials that seemed of interest were screened. Only those which compared any type of vitamin D with a matching placebo in a double-blind fashion (i.e. neither the subject nor the investigating physician knew which treatment the subject was given) were considered further.

After screening, 5 studies were found that fitted the criteria. There were 1237 subjects in all, with an average age of 70; 81% of the subjects were women. In two of the studies, daily vitamin D supplements plus calcium supplements were compared with calcium supplements alone. In the other three, vitamin D supplementation (vitamin D itself or a related compound) were compared with placebo. Treatments were given for at least 2 months for up to 3 years. Falls were defined as "coming to rest on the ground, floor, or other lower level".

Five additional studies were included in the second part of the analysis; these had less rigid criteria - for instance, they didn't define falls exactly.

What was found out

Only one of the five primary studies showed a significant link between the vitamin D intake and a reduction in falls. However, when the results of all 5 studies were pooled, it was clear that there was a reduction in the risk of falling by 22%. In other words, for every 100 subjects not taking vitamin D supplements who had falls, only 78 of those taking supplements would fall.

When the additional 5 studies were included in the analysis, there were over 10,000 subjects. This analysis, using a very large but slightly less acceptable data base, showed a smaller but still significant reduction in falls - 13% - in vitamin D users.

What this means

Vitamin D supplements reduced the risk of falls in older people by more than 20%. This shows that the benefits of vitamin D in osteoporosis patients are not confined to helping improve bone mineral density; they help prevent the falls that, in osteoporotic people, lead to fractures.

The explanation for this effect of vitamin D is that a breakdown product of the vitamin, 1,25-hydroxyvitamin D, combines with a specific part of the nucleus of muscle cells, and improves that cell's ability to contract.

Of course, there will be further studies on the different types of vitamin D supplements and the best doses to use, and whether the addition of calcium is important. However, there's no reason to wait until these are completed. Elderly people should make sure they are getting enough vitamin D - probably as much as 800 IU a day - either in their food, or with appropriate exposure to sunlight, or as a supplement. And, of course, they should make sure that their homes and surroundings are 'fall-safe' - see the links below.


  • Effect of vitamin D on falls. HA. Bischoff-Ferrari, B. Dawson-Hughes, WC. Willett,  et al., JAMA, 2004, vol. 291, pp. 1999--2006


Related Links
How To Avoid Falls at Home
Preventing Falls

Created on: 08/16/2004
Reviewed on: 12/22/2009

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