Can Supplementation with Vitamin D Reduce the Risk of Falls in Older Adults?

Abstract & Commentary

By James C. Scheer, DO, MS. Dr. Scheer is Associate Medical Director, NorthEast Internal & Integrative Medicine of Carolinas Medical Center-NorthEast in Concord, NC; he reports no financial relationship to this field of study.

Synopsis: A meta-analysis of eight randomized controlled trials (n = 2,426) of supplemental vitamin D showed a dose of 700-1,000 IU/d reduced fall risk in older individuals by 19% (or by 26% with vitamin D3). Vitamin D doses < 700 IU/d or serum 25-hydroxyvitamin D levels < 60 mmol/L (24 ng/mL) may not reduce the risk of falling among older individuals.

Source: Bischoff-Ferrari HA, et al. Fall prevention with supplemental and active forms of vitamin D: A meta-analysis of randomized controlled trials. BMJ 2009;339:b3692.

The authors of this meta-analysis set out to assess the efficacy of vitamin D supplementation, with and without calcium, for the prevention of falls among older persons. Their analysis evaluated vitamin D both by dose and by serum concentration of 25(OH)D achieved.

A systematic search for articles in a variety of databases (BIOSIS, Embase, Medline, and Cochrane central register of controlled trials) was performed. A total of 164 articles were found that met initial criteria from randomized controlled trials of fall prevention with a defined oral dose of vitamin D2 or D3 in individuals age 65 years or older with a minimum follow-up of 3 months. After exclusion criteria were applied (e.g., not randomized, low adherence rates, reviews, no controls, etc.), a total of eight randomized clinical trials were included in the final meta-analysis.

The eight trials involved 2,426 individuals, 81% of whom were female, with a mean age of 80 years. All participants were in stable health and were living in the community or in nursing homes. Vitamin D3 was used in five studies and vitamin D2 in three studies. Supplemental vitamin D was given in daily doses ranging from 200 IU to 1,000 IU. Treatment duration ranged from 2 months to 36 months.

All trials assessed vitamin D treatment for the prevention of falls as a primary or secondary outcome. The pooled relative risk for any dose of vitamin D preventing a fall was 0.87. The pooled relative risk for the seven studies with 700-1,000 IU/d of supplemental vitamin D (n = 1,921) was 0.81, suggesting that a high daily dose of vitamin D reduced the risk of a person falling by 19%. The pooled relative risk for the two trials with a daily dose < 700 IU (200-600 IU) of vitamin D was 1.10, indicating that a low dose did not reduce fall risk.

Achieved serum 25(OH)D concentrations 3 60 mmol/L resulted in a 23% fall reduction, whereas concentrations < 60 mmol/L had no effect on number of falls (pooled relative risk, 1.35).

In subgroup analyses of trials that assessed the high dose of supplemental vitamin D (700-1,000 IU/d), the pooled relative risk reduction was 12% in the trials that used vitamin D2 compared to 26% for trials that used vitamin D3.

Further subgroup analyses showed no significant differences when adjusting for: calcium supplementation, age (3 65-75 years), active vs. supplemental forms of vitamin D, or ambulatory vs. institutionalized persons.

Commentary

Falls are the leading cause of accidental death among people age 65 years and older. They also account for significant morbidity, including fracture, impaired mobility, decreased quality of life due to fear of falling and depression.1 Each year, one in three people age 65 years and older experience at least one fall. More than 30% of these falls result in an injury requiring medical attention or restriction of activities for at least one day. Up to 15% of falls in this age group result in fracture. For the year 2000, $19 billion was spent in the United States on direct medical costs of fall-related injuries — nearly half of which was related to hip fractures.2

This meta-analysis was restricted to studies that utilized a double-blind design and had sufficient fall assessment quality to address the efficacy of vitamin D for fall prevention. The study does confirm findings from an earlier meta-analysis in 2004,3 which showed that any vitamin D supplementation reduced falls in older individuals by 22%. Interestingly, in the earlier analysis, the low dose (400 IU/d) of vitamin D showed a neutral effect, whereas two trials with 800 IU/d showed a beneficial effect on risk of falls.

Further supporting the findings of the current study are the results from double-blind randomized clinical trials documenting fracture prevention with 700-800 IU/d of vitamin D,4,5 but not with 400 IU/d.6 And similar to the current study, a 2008 study found a significantly lower risk of hip fracture with 25(OH)D levels > 60 mmol/L.7

Unfortunately, Bischoff-Ferrari et al offer no explanation as to why in the low-dose vitamin D trials (200 IU, 400 IU, and 600 IU) the control groups had serum 25(OH)D levels that increased on average the same amount (11-12 mmol/L) as the treatment groups after 5 months (total, n = 151 participants). Possible explanations include: 1) the studies were not properly controlled (e.g., the control groups had access to supplemental vitamin D through their diet, multivitamin, or other supplement, or sunshine exposure), or 2) low-dose vitamin D (< 800 IU/d) has little effect on serum vitamin D levels.

The authors do discuss that vitamin D deficiency can lead to muscle weakness, which may explain the higher risk for falls. Muscle weakness, in this vitamin-deficient state, may be explained by a loss of type II muscle fibers and atrophy of proximal muscles.8 In contrast, it has also been suggested that vitamin D at adequate levels reduces body sway.9

A 2009 Cochrane review of this subject concludes that taking vitamin D supplements probably does not reduce falls, except in people who have a low level of vitamin D in the blood.10 Further, these supplements may be associated with high levels of calcium in the blood, gastrointestinal discomfort, and kidney disorders.

Yet, according to the Third National Health and Nutrition Examination Survey (NHANESIII), 61% of white and 91% of black Americans suffer from vitamin D insufficiency, as defined by 25(OH)D < 32 ng/mL (80 mmol/L).11

In their discussion, the authors of the meta-analysis mention that they found a greater fall reduction in studies with a maximum vitamin D daily dose of 1,000 IU than in studies with lower doses; therefore, they suggest that higher doses may be even more effective.

Thus, vitamin D supplementation in any form may significantly reduce fall risk in the elderly. A daily intake of 700-1,000 IU of vitamin D appears to be an adequate prophylactic dose. However, vitamin D3 may be more effective than vitamin D2 based on the current study. Vitamin D supplementation may be more critical in people with a true deficiency, so levels of 25(OH)D should be checked routinely in people age 65 and older (for more on vitamin D, see the March and April 2009 issues of Alternative Medicine Alert). A threshold serum level is likely between 60-80 mmol/L (24-32 ng/mL) that minimizes both fall and fracture risk.

References

1. Tinetti ME, et al. Risk factors for falls among elderly persons living in the community. N Engl J Med 1988;319:1701-1707.

2. Stevens JA, et al. The costs of fatal and non-fatal falls among older adults. Inj Prev 2006;12:24-35.

3. Bischoff-Ferrari HA, et al. Effect of vitamin D on falls: A meta-analysis. JAMA 2004;291:1999-2006.

4. Trivedi DP, et al. Effect of four monthly oral vitamin D3 (cholecalciferol) supplementation on fractures and mortality in men and women living in the community: Randomized double blind controlled trial. BMJ 2003; 326:469-474.

5. Dawson-Hughes B, et al. Effect of calcium and vitamin D supplementation on bone density in men and women 65 years of age or older. N Engl J Med 1997;337:670-676.

6. Meyer HE, et al. Can vitamin D supplementation reduce the risk of fracture in the elderly? A randomized controlled trial. J Bone Miner Res 2002;17:709-715.

7. Looker AC, Mussolino ME. Serum 25-hydroxyvitamin D and hip fracture risk in older U.S. white adults. J Bone Miner Res 2008;23:143-150.

8. Sato Y, et al. Changes in the supporting muscles of the fractured hip in elderly women. Bone 2002;30:325-330.

9. Pfeifer M, et al. Effects of a short-term vitamin D and calcium supplementation on body sway and secondary hyperparathyroidism in elderly women. J Bone Miner Res 2000;15:1113-1118.

10. Gillespie LD, et al. Interventions for preventing falls in older people living in the community. Cochrane Database Syst Rev 2009;2:CD007146.

11. Looker AC, et al. Serum 25-hydroxyvitamin D status of adolescents and adults in two seasonal subpopulations from NHANES III. Bone 2002;30:771-777.