Taking 800-2,000 IUs of vitamin D per day significantly reduces the risk of most fractures in men and women age 65 and older. In a study, the top 25% of Vitamin D consumers sustained 30% fewer hip fractures and 14% fewer fractures of other bones. There was no benefit to taking Vitamin D supplements in doses below 800 IUs. The cost of treating a hip fracture is $26,912.
New England Journal of Medicine, June 2012