Vitamin D2 May Help Prevent Falls Among High-Risk Older Women

By Judith Groch
Vitamin D2 supplements appeared to reduce the risk of falls, especially during the winter months, among high-risk older women living in otherwise sunny climates, researchers in Australia reported.
Older women with a vitamin D deficiency who were given vitamin D2 (ergocalciferol) and calcium supplements had a 19% lower risk of falls compared with patients given calcium alone, Richard L. Prince, M.D., of the University of Western Australia here, and colleagues reported in the Jan. 14 issue of the Archives of Internal Medicine.
Approximately one-third of women older than 65 fall each year, and 6% of those sustain a fracture as a result, the researchers wrote. In addition, fear of falling is a major problem for older women.
It's known that vitamin D2 plays a role in fall prevention, but the effect in patients living in sunny climates remains uncertain, the researchers said.
So they did a one-year, double-blind, randomized controlled trial of 302 community-dwelling women ages 70 to 90, living in Perth, Australia (latitude, 32°S). The women had a history of falling in the previous year.
Because the study was conducted in a sunny climate, the researchers selected women with a serum 25-hydroxyvitamin D concentration of less than 24.0 ng/mL.
Half the participants were randomized to receive vitamin D2 (ergocalciferol), 1,000 IU a day, or a placebo. Both groups received calcium citrate (1,000 mg/d), which the researchers said they had previously shown to reduce fracture risk. Fall data were collected every six weeks.
There were no differences between the groups in any baseline characteristics except that the women in the vitamin D2 group were considerably shorter, probably because randomization failed to equalize the height differences, a significant drawback. Height was possibly correlated with the strength of muscle groups, the researchers said.
Vitamin D2 therapy reduced the risk of at least one fall over one year after adjustment for baseline height (vitamin D2 group, 53%, 80 women; control group, 62.9%, 95 women; odds ratio: 0.61, 95% confidence interval: 0.37 to 0.99), representing a 19% relative risk reduction.
Because height was a significant predictor of falling, the fall data were adjusted for height differences.
When those who fell were grouped by the season of the first fall, vitamin D2 treatment reduced the risk of having the first fall mainly in winter and spring (vitamin D2 group, 25.2%; control group, 35.8%; OR: 0.55, 95% CI: 0.32 to 0.96) but not in the sunnier months of summer and autumn.
While vitamin D2 therapy reduced the number of women who sustained one fall during the winter/spring season, the treatment did not decrease the number who had multiple falls.
This result, they said, is supported by a previous study, which found that women with frequent falls failed to benefit from treatment with cholecalciferol (vitamin D3) and calcium.
Older people who fall frequently tend to have more risk factors for falling, including greater degrees of disability and poorer levels of physical function, the researchers noted.
Thus, it is possible, they said, that biochemical correction of a serum vitamin D deficiency is insufficient to prevent falls in this particular population.
A weakness of the study, the researchers wrote, is that the randomization failed to correct for height, which proved to be an important covariate.
It should also be noted, they said, that this study used ergocalciferol (vitamin D2) rather than the more potent cholecalciferol (vitamin D3). Therefore, the effect of Vitamin D3 on the reduction of falls could be greater, they said.
Because supplementation had no effect on fall reduction in summer, when mean levels of serum vitamin D are achieved with increased solar radiation, the researchers proposed that serum vitamin D averaging 21.7 ng/mL should be considered adequate to prevent risk of falling as a result of vitamin D deficiency in elderly women. In individual patients known to be at risk for falling, it would be reasonable to aim for levels of 24.0 ng/mL or higher, they concluded.
This study was supported by a research grant from the National Health and Medical Research Council of Australia. The Boots Company of Australia supplied the ergocalciferol preparation (Ostelin) and identical placebo free of charge. Mission Pharmaceutical supplied the calcium citrate free of charge.
The authors reported no financial conflicts.
Primary source: Archives of Internal MedicineSource reference:Prince R, et al "Effects of ergocalciferol added to calcium on the risk of falls in elderly high-risk women" Arch Intern Med 2008; 168: 103-108.