9 November 2009
This meta-analysis found that high-dose vitamin D supplements reduced the relative risk of falling by 19% in individuals aged 65 years or more. Eleven people would need to be treated with 700 to 1000 units of vitamin D daily to prevent one fall over about 21 months*. Falls were not significantly reduced by low-dose vitamin D supplements.
* The average duration of treatment that the patients in the trials included in the meta-analysis received.
Level of evidence:
Level 2 (limited-quality patient-oriented evidence) according to the SORT criteria.
Healthcare professionals should follow the NICE guideline on the assessment and prevention of falls in older people, and the two NICE technology appraisals on the use of drugs for the primary and secondary prevention of osteoporotic fragility fractures in postmenopausal women with osteoporosis. The technology appraisals assume that women who receive treatment have an adequate calcium intake and are vitamin D replete. Unless clinicians are confident that women who receive treatment meet these criteria, calcium and/or vitamin D supplementation should be considered. There are a number of licensed preparations that will supply the evidence-based doses of 1g per day for calcium (measured as elemental calcium) and 700 to 1000 units per day for vitamin D.
What is the background to this?
Vitamin D supplementation can improve muscle strength, function and balance in a dose-related manner in older individuals at risk of vitamin D deficiency. However, it is unclear whether vitamin D can prevent falls because results from studies have been inconclusive. This meta-analysis assessed the efficacy of supplemental vitamin D and active forms of vitamin D, with and without calcium, for the prevention of falls among older people, by dose and by serum concentration of 25-hydroxyvitamin D3.
What does this study claim?
This study found that doses of vitamin D supplements in the range of 700 to 1000 units daily gave a relative risk reduction (RRR) of falling by 19% (7 randomised controlled trials [RCTs], n=1,921; relative risk [RR] 0.81, 95%CI 0.71 to 0.92; pooled risk difference 9.4%, 95%CI 5.1% to 13.7%; number needed to treat [NNT] 11, 95%CI 7 to 20) over about 21 months* (range 2 to 36 months). Doses of less than 700 units daily did not significantly reduce fall risk.
The NICE guidance on falls prevention does not currently make any recommendations on the use of vitamin D. It points out that there is evidence that vitamin D deficiency and insufficiency are common among older people and that, when present, they impair muscle strength and possibly neuromuscular function. Although, as this meta-analysis shows, there is emerging evidence that correction of vitamin D deficiency or insufficiency may reduce the propensity for falling, there remains uncertainty about the relative contribution to fracture reduction. Combined calcium and vitamin D supplementation has been shown to prevent fractures in studies of people living in care homes and/or the frail elderly. However, it is unclear whether the results are generalisable to women living in the wider community.
Risk assessment is important in osteoporosis to target the effective therapies to those at highest risk of falls and fracture. For the lower-risk population, advice to ensure sufficient calcium and vitamin D intake, perhaps using educational materials, is probably appropriate. Supplementation may be considered for those with diets that have poor intake of calcium-rich foods or who have limited exposure to sunlight. The Food Standards Agency website outlines which foods are good sources of calcium and vitamin D.
Those at higher risk of falls and fracture, such as those in nursing or residential homes, should be considered for additional supplementation, at an evidence-based dose. Importantly, this includes those on a bisphosphonate or other osteoporosis treatment, as all of the trials were conducted in people with optimal calcium and vitamin D intake. For postmenopausal women receiving treatment for the primary or secondary prevention of osteoporotic fractures, NICE states that supplements may be considered for those who do not have an adequate calcium intake and who may not be vitamin D replete. There are a number of licensed preparations that will supply the evidence-based doses of 1g per day for calcium and 700 to 1000 units per day for vitamin D, and practitioners should ensure that this is the case when prescribing, dispensing or administering this treatment. See the BNF for more details.
NICE is developing a clinical guideline on ‘Osteoporosis: assessment of fracture risk and the prevention of osteoporotic fractures in individuals at high risk’. The development of this is currently being reviewed following the publication of the technology appraisals.
A suite of educational materials on osteoporosis, including a <60minute eLearning event, is now available on NPCi.
Design: Meta-analysis of 10 RCTs of fall prevention (sufficiently specified) with a defined oral dose of vitamin D supplement (D2 or D3) or active vitamin D and a minimum follow-up of 3 months.
Patients: 3,050 individuals aged 65 years or older.
Intervention and comparison: The primary outcome measure was the relative risk of having at least one fall among persons receiving vitamin D, with or without calcium, compared with the risk among those receiving placebo or calcium supplementation alone.
Outcomes and results: Heterogeneity was found among the results for the 8 RCTs looking at fall prevention with any dose of supplemental vitamin D. However this was resolved after stratifying trials by daily dose.
Doses of vitamin D supplements in the range of 700 to 1000 units daily reduced the relative risk of falling by 19% (7 RCTs, n=1,921; RR 0.81, 95%CI 0.71 to 0.92; pooled risk difference 9.4%, 95%CI 5.1% to 13.7%; P<0.0001; NNT 11, 95%CI 7 to 20) for a treatment duration of about 21 months* (range 2 to 36 months). Doses of less than 700 units daily did not significantly reduce fall risk (2 RCTs, n=505; RR 1.10, 95%CI 0.89 to 1.35). Similarly, achieving a serum concentration of 25-hydroxyvitamin D3 of 60nmol/L or more significantly reduced the risk of falling (RR 0.77, 95%CI 0.65 to 0.90) whereas a concentration of less than 60nmol/L did not (RR 1.35, 95%CI 0.98 to 1.84).
Subgroup analysis suggested that the benefit of high-dose vitamin D was not significantly affected by type of vitamin D (D2 or D3), gender, age, or level of independence and was attained with only 2 to 5 months of treatment and sustained for 12 to 36 months. In addition, fall prevention with a high dose may not depend on additional calcium supplementation. However, because these results are based on subgroup analyses, they should only be regarded as hypothesis generating.
Oral active forms of vitamin D significantly reduced the risk of falling (2 RCTs, n=624; RR 0.78, 95%CI 0.64 to 0.94)
Sponsorship: Swiss National Foundations Professorship Grant , Velux Foundation, Baugarten Foundation, Vontobel Foundation, fellowship from Robert Bosch Foundation, National Institute on Aging
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