Vit D supps "reduce fracture risk up to 20%"

Oral vitamin D supplements at a dose of at least 400 international units per day are associated with a reduced risk of bone fractures in  older adults, according to results of a meta-analysis published in the  March 23 issue of Archives of Internal Medicine.

"The anti-fracture benefits of vitamin D have been questioned by  several recent trials," the authors write, adding that "factors that may  obscure a benefit of vitamin D are low adherence to treatment, low dose  of vitamin D or the use of less potent ergocalciferol (vitamin D2)."

The scientists performed a meta-analysis on 12 previously-published  clinical trials involving 42,279 participants and found that vitamin D  supplements decreased the risk of non-vertebral fractures by 14% and of  hip fractures by 9%. The authors then pooled the results of only nine  trials in which subjects received doses of more than 400  international units per day. At this higher dosage, vitamin D reduced  non-vertebral fractures by 20% and hip fractures by 18%. Lower doses did  not cut the risk of either fracture type. A greater reduction was also  seen among trial participants whose blood levels of 25-hydroxyvitamin  D - a commonly used measure of blood vitamin D levels - achieved a  greater increase.