Critique date: Mon, 01/31/2005 - 1:10pm
Article Citation
Citation:
Bischoff-Ferrari HA, Dawson-Hughes B, Willett WC, Staehelin HB, Bazemore MG, Zee RY and Wong JB . Effect of Vitamin D on Falls: A Meta-Analysis. JAMA. 2004;291(16):1999-2006.
Clinical Bottom Lines
Vitamin D supplementation reduced the odds of falling in an elderly population by 22% (95% CI: 8-36%) compared to those not receiving Vitamin D.
The number-needed-to-treat to prevent 1 person from falling was 15 (95% CI, 8-53).
Methods
Patient Population:
The review identified 5 RCTs with a total of 1,237 subjects. Participants were predominantly female (80.7%) with a mean age >70 years in all of the studies. 62% were community dwelling; 38% resided in assisted living centers. The vast majority of men (78%) were community dwelling.
Inclusions
Double blind RCT's involving any type of Vitamin D and its effect on low trauma falls in the elderly. All studies had to explicitly state how falls were defined and how they were measured.
Significant Exclusions:
Uncontrolled trials or observational studies were excluded as well as studies involving patients with unstable health states which might increase the risk for falls, such as alcoholics and subjects who had just had an acute illness requiring hospitalization. High trauma falls, such as falls from ladders, were excluded.
Intervention/Exposure:
Identified studies used several different forms of Vitamin D supplements with or without calcium in both intervention and control groups and with varying exposure and follow-up periods.
Â
Vitamin D intervention
Both Groups Given Calcium
Duration of intervention
Duration of follow-up
Dropouts
Pfeifer, 2000
800 IU Vit D3
1200 mg
3 months
3 months
7%
Bischoff, 2003
800 IU Vit D3
1200 mg
2 months
1 year
28%
Graafmans, 1996
400 IU Vit D3
800-1000 mg from dairy
7 months
7 months
Not stated
Gallagher, 2001
0.5 m g Calcitriol
None
3 yrs
3 yrs
15%
Dukas, 2004
1 m g of 1 µ- calcidiol
None
9 months
9 months
13%
Analysis
Intention-to-treat. Heterogeneity between studies was assessed and found not to be significant. A sensitivity analysis was performed that included 5 additional RCTs, which had been excluded from the primary analysis due to a lack of a definition of falls.
Outcome Measures:
Primary Outcome
Relative risk of having at least 1 fall among persons receiving Vitamin D compared with those not receiving Vitamin D.
Secondary Outcomes
None
Participant Follow-up:
Of the 5 identified studies 1 did not list the number of dropouts. For the remaining studies, dropout was 7%, 13%, 15% and 28%, as noted in the above table. The study with 28% dropout (Bischoff, 2003) was conducted in patients in an assisted living center awaiting nursing home placement and thus high dropout was expected and was considered in the study design.
Conclusion
Results:
Â
Pooled OR (95% CI)
Uncorrected
0.69 (0.53-0.88)
Corrected for the tendency of odds ratios to overestimate the relative risk with common events
0.78 (0.64-0.92)
Corrected, and including 5 additional studies with 8,764 subjects
0.87 (95% CI 0.65-0.96).
PostHoc analyses, corrected:
Â
Active Vitamin D (calcitriol and 1 µ –calcidiol)
0.71 (95% CI 0.55-0.92)
800 IU of Cholecalciferol
0.65 (95% CI 0.40-1.00)
800 IU or 400 IU of Cholecalciferol
0.83(95% CI 0.65-1.06)
Number needed to treat to prevent one person from falling was 15 (95% CI, 8-53).
Subgroup analyses for different lengths of treatment and follow-up as well as sex did not reveal any differences in the main effect. It was impossible to examine whether there was an additive effect of calcium combined with Vitamin D due to the design of the studies.
Concerns Regarding Methodology, Applicability to Older Adults, etc.:
Comments
The authors cite research suggesting that the decrease in falls is mediated by a direct effect of Vitamin D on muscle function.
The ideal dose and form of Vitamin D could not be determined, although the authors suggest that there is plausible evidence that 800 IU of Cholecalciferol per day may be more effective than 400 IU.
The role of calcium in this effect is unclear, however the authors note that in the study by Dukas only subjects with total dietary calcium greater than 512 mg/day had a significant reduction in falls (Dukas, 2004).
Also, while one might assume that the use of Vitamin D at the studied doses is relatively cheap and with low risk of adverse effects, no formal assessment of safety or cost effectiveness was made.
Funding Source and Role:
Harvard/Hartford Foundation, Charles A. King Trust Fellowship Award, The Stare Nutrition Education Fund, The Swiss Foundation for Nutrition Research and the International Foundation for the Promotion of Nutrition Research and Education. None of the sponsors participated in the design or conduct of the study nor in the collection, analysis and interpretation of the data or the preparation of the review.
Created By:
Michael Bogaisky, MD, MPH, First Year Geriatrics Fellow, Brookdale Dept. of Geriatrics and Adult Development, Mt. Sinai School of Medicine
This is a review of the validity of a single study; the ‘bottom lines’ do not reflect comparison with the rest of the literature on this subject.