PERTH, Australia—Adding 1000 IU/day of ergocalciferon (vitamin D2) to calcium supplementation can reduce falls by 19% in high-risk elderly women, Australian researchers report in Archives of Internal Medicine. The improvement was greater for first falls occurring in winter/spring than for those occurring in summer/autumn.

In a 1-year population-based, double-blind, randomized controlled trial of 302 community-dwelling ambulatory women aged 70 to 90 years, Richard L. Prince, MD, et al report, "[T]he effectiveness of the intervention could be considered to be the result of the maintenance of higher summer/autumn 25-OHD [25-hydroxyvitamin D] levels, attained through increased exposure to UV-B, through winter/spring."

Community-dwelling elderly women with low 25-OHD levels and a history of falling

Dr. Prince, of the department of endocrinology and diabetes at Sir Charles Gairdner Hospital in Nedlands, Australia, studied women living in sunny Perth with serum 25-OHD concentrations <24 ng/mL and a history of falling in the previous year. All subjects received calcium citrate 1000 mg/day; 151 women randomized to ergocalciferol 1000 UI/day and 151 to placebo. Calcium was taken as two 250-mg tablets with breakfast and two 50-mg tablets with the evening meal. Ergocalciferol or identical placebo was taken with the evening meal.

"Because the study was undertaken in a sunny climate, the women were selected to have a vitamin D insufficiency or deficiency with a serum 25-OHD level <24 ng/mL, approximately the median level for 25-OHD levels in older women in Western Australia," the investigators wrote.

Every 6 weeks staff interviewed subjects by telephone or during clinic visits about the number of falls in the previous 6 weeks and the features of the falls. At least one fall over the study period occurred in 53% of the ergocalciferol group and in 62.9% of the control group (OR, 0.66, 95% CI, 0.41-1.06). "Ergocalciferol therapy significantly reduced the proportion of patients who had their first fall in winter/spring...but not those who had their first fall in summer/autumn," Dr. Prince noted.

This difference was parallel by the effects of ergocalciferol supplementation on 25-OHD levels, which rose proportionately more during summer/autumn than in winter/spring.

"This study showed that supplementation with ergocalciferol and calcium is associated with a 19% reduction in the relative risk of falling in noninstitutionalized women with vitamin D insufficiency and high risk of falling compared with patients given calcium alone." Dr. Prince noted that seasonal variations in hip fracture rates have also been reported, with more fractures occurring in colder months. "Taken together, these studies suggest that low 25-OHD status associated with reduced UV radiation in colder months increases the risks of falls and hip fracture and may account, in part, for the effectiveness of the combination of vitamin D and calcium on the prevention of hip fracture."

Translating research into practice

Further analysis showed no significant effect on falls reduction in summer when mean levels of 25-OHD were 21.7 ng/mL due to increased incident solar radiation.

"Ergocalciferol, 1000 IU/day, added to a high calcium intake is associated with a 23% reduction in the risk of falling in winter/spring, to the same level as in summer/autumn. Thus, we propose that 25-OHD levels averaging 21.7 ng/mL should be considered as adequate to prevent the risk of falling owing to vitamin D deficiency in elderly women living in the community. In individual patients at risk of falling, it would be reasonable to aim to achieve 25-OHD levels of 24 ng/mL or higher," Dr. Prince concluded.

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