Osteoporosis (reduced bone mineral density) is most common in older adults, particularly women. It is a major risk factor for bone fractures that will become a bigger and more costly problem unless something is done to prevent it. While vitamin D has been shown to reduce the risk of fracture in the elderly certain questions regarding how much of Vitamin D is needed has to be answered.
The Recommended Dietary Allowance of vitamin D for older adults is between 400 and 600 International Units (IU) per day. It has been found that this dose is not very effective in reducing nonvertebral fracture rates among the members studied. On the other hand, higher daily doses, in the range of 700 to 800 IU, may reduce the risk of fracture by approximately 25 percent.
This would mean a careful reconsideration of the current recommended daily values of vitamin D for older adults in addition to looking more closely at the possible role that calcium supplementation may have in mediating the effects of vitamin D.