Dr. Kenneth Madden (biography and disclosures)
What I did before
Every year, one-third of older adults (age greater than 65) experience one or more falls.1 One therapy with the potential to reduce both falling and fractures is vitamin D supplementation, possibly due to a direct stimulation of vitamin D receptors on muscle tissue.2 Often the patients that would most benefit from vitamin D (frail older adults with frequent falls) have swallowing issues that make swallowing large vitamin pills difficult. Since “there is no correct dose” and it is “only a vitamin” I often administered larger doses (such as yearly courses of 50 000 IU cholecalciferol once per week X 8 weeks) to make administration easier for patients with swallowing issues.
What changed my practice
Unfortunately, a closer look at the issue revealed the appropriate dose of vitamin D necessary to safely reduce fall and fracture risk remains controversial. A recent meta-analysis of all studies done to date3 demonstrated that “high dose” vitamin D reduced falls by 23 percent (RR 0.77, 95% confidence interval 0.71 to 0.92) when “high dose” was defined as 700 to 1000 IU per day. Lower doses (less than 700 IU) had no effect on fall risk. The effects of doses higher than 1000 IU had not been examined previously to the publication of this meta-analysis. It is also important to remember that large doses of vitamins are not necessarily benign; the increase in mortality with high-dosage vitamin E4 should serve as a cautionary example.
After the publication of the above meta-analysis, a randomized, controlled, double blind study5 examined the effect of a massive yearly doses of vitamin D on falls and fractures. The investigators recruited a large number of older adult women (median age of 76 years, n=2258) that were at high risk for falls (defined as the subject being a self-reported faller, having a previous fracture, or having a family history of maternal hip fracture). The study intervention was 500 000 IU cholecalciferol given as 10 tablets taken on a single day. Unfortunately, the large-dose vitamin D group both fell and had more fractures than the placebo group. In fact, there was approximately one more fracture per 100 person-years in the vitamin D group as compared to the placebo group. Of even more concern, fracture rates in the treatment group were highest in the first 3 months following the large dose of vitamin D, suggesting a direct toxic effect.
What I do now
There is support for using vitamin D to prevent falls in older adults, but only in a dose ranging from 700 IU to 1000 IU per day. I no longer give patients larger doses of vitamin D at less frequent intervals; in fact this practice might have been causing harm. There is no literature to determine what the impact of a more temperate but larger dose of vitamin D will have on fall and fracture rates. Like any other medication, large doses of vitamins can be harmful.
References: (Note: Article requests require a login ID with CPSBC or UBC)
- Tinetti ME, Speechley M, Ginter SF. Risk factors for falls among elderly persons living in the community. N Engl J Med 1988;319:1701-7. (View article with CPSBC or UBC)
- Bischoff-Ferrari HA, Borchers M, Gudat F, Durmuller U, Stahelin HB, Dick W. Vitamin D receptor expression in human muscle tissue decreases with age. J Bone Miner Res 2004;19:265-9. (View article with CPSBC or UBC)
- Bischoff-Ferrari HA, Dawson-Hughes B, Staehelin HB, et al. Fall prevention with supplemental and active forms of vitamin D: a meta-analysis of randomised controlled trials. BMJ 2009;339:b3692. (View article with CPSBC or UBC)
- Miller ER, 3rd, Pastor-Barriuso R, Dalal D, Riemersma RA, Appel LJ, Guallar E. Meta-analysis: high-dosage vitamin E supplementation may increase all-cause mortality. Ann Intern Med 2005;142:37-46. (View article with CPSBC or UBC)
- Sanders KM, Stuart AL, Williamson EJ, et al. Annual high-dose oral vitamin D and falls and fractures in older women: a randomized controlled trial. JAMA 2010;303:1815-22. (View article with CPSBC or UBC)
Notes from the BC Guidelines
There is good evidence that supplementation with at least 800 international units (IU) of vitamin D3 per day, combined with calcium, is required to reduce the risk of fragility fractures, therefore 800 – 1000 IU daily is recommended (although the optimum daily requirement of vitamin D3 is not known).4,5,6 Weekly dosing (one week’s adult dose of vitamin D3 taken as a single weekly dose, i.e. 7000 IU) or monthly dosing (one month’s adult dose of vitamin D3 taken once a month, i.e. 30,000 IU) may be more convenient for some patients and has been shown to be safe.1,4,7 At this time, high doses of vitamin D3 once a year is not recommended as recent evidence has shown possible increased fracture risk.8
Population at Risk
The BC population is at risk of low vitamin D levels from autumn to spring. There is no clinical utility in performing vitamin D tests on patients who are thought to be at risk for sub-optimal vitamin D levels and who would benefit from vitamin D supplementation.
Vitamin D Supplementation without Testing
Because vitamin D supplementation in the general adult population is safe, it is reasonable to advise supplementation without testing. Routine testing of vitamin D levels [25-hydroxyvitamin D or 25(OH)D] is not medically necessary prior to or after starting vitamin D supplementation.
Utilization and Cost of Serum Vitamin D Testing in BC
Utilization of vitamin D testing [as 25(OH)D] in BC has increased ten-fold in the past five years. Medical Service Plan expenditures are approximately $3 million annually for outpatient vitamin D testing with a cost per test of $93.63 in 2009.