HONOLULU, Hawaii—Researchers at the American Society for Bone and Mineral Research (ASBMR) 29th Annual Meeting reported that vitamin D and calcium supplementation decreases the risk of falling among postmenopausal women and that the ability of vitamin K₁ to prevent falls and fractures is not due to preventing loss of bone mineral density (BMD).^1,2

Vitamin D + calcium reduce risk of repeated falling

Merja Kärkkäinen, PhD, and colleagues with the bone and cartilage research unit at Kuopio University Hospital, in Finland, reported that giving ambulatory postmenopausal women 800 IU of vitamin D (cholecalciferol) and 1000 mg of calcium each day did not reduce the number of falls for the groups as a whole (compared with placebo) but did reduce the number of falls per person.¹

"It could be hypothesized that a single fall is more accident-related and unrelated to functional capacity. On the other hand, subsequent falls might indicate disorders in subject balance, muscle strength, or both," Dr. Kärkkäinen said.

The population-based, randomized, 3-year study included 1718 women given supplements for 3 years and a control group of 1714 women given no supplements as well as a randomized subsample of 606 women. All three groups were surveyed for falls by telephone once per year, but the more intensively studied subsample was surveyed every 4 months and was also tested for functional capacity and strength.

"[S]ince the supplementation prevented only multiple falls, we suggest that only recurrent fallers benefit from calcium and vitamin D supplementation. Due to the high incidence of vitamin D deficiency, high disability, economic costs of falls, and on the other hand the well-tolerated and effective product, these results are promising for considering vitamin D and calcium supplementation to elderly women for fall prevention," Dr. Kärkkäinen concluded.

Vitamin K does not work by protecting BMD

Meanwhile, Angela M. Cheung, MD, PhD, and colleagues with the University Health Network, in Toronto, Canada, concluded that whatever vitamin K1 is doing that prevents falls is not due to protection of BMD.²

"Daily K₁ supplementation (5 mg) did not protect against age-related decline in BMD....The effect of K₁ on bone may not be mediated by BMD or bone turnover," wrote Dr. Cheung, who noted that another recent study suggested that vitamin K₂ improves bone strength via bone geometry rather than BMD.

The investigators concluded, "Vitamin K₁ supplementation at a daily dose of 5 mg does not protect against age-related decreases in BMD, but may reduce the incidence of fractures and cancers in postmenopausal women with osteopenia. Before K₁ supplementation can be recommended for general use, further studies must be done to better understand the mechanisms behind these findings."

References

1. Kärkkäinen M, Tuppurainen M, Rikkonen T, et al. Vitamin-D 800 IU + calcium 1000 mg supplementation decreases the risk of falling among postmenopausal ambulatory women—population-based, randomized, 3-year study (OSTPRE-FPS). Presented at: ASBMR 29th Annual Meeting; September 16-19, 2007; Honolulu, HI. Abstract S452.
2. Cheung AM, Tile L, Lee Y, et al. Vitamin K supplementation in postmenopausal women with osteopenia: the ECKO trial. Presented at: ASBMR 29th Annual Meeting; September 16-19, 2007; Honolulu, HI. Abstract S399.