Higher doses of Vitamin D might be beneficial in reducing bone fractures in seniors, a researcher says, citing the results of a pooled analysis of 11 unrelated, randomized clinical trials investigating vitamin D supplementation and fracture risk in more than 31,000 older adults.

As part of the study, published earlier this month in The New England Journal of Medicine, senior author Dr. Bess Dawson-Hughes and colleagues divided the subjects into quartiles ranging from 0 to 2,000 international units (IUs) of daily vitamin D intake. The top quartile sustained 30 percent fewer hip fractures and 14 percent fewer fractures of other bones compared to the control groups.

"Taking between 800 IUs and 2,000 IUs of vitamin D per day significantly reduced the risk of most fractures, including hip, wrist, and forearm in both men and women age 65 and older," says Dawson-Hughes, who is director of the bone metabolism laboratory at Boston-based Tufts University. "Importantly, we saw there was no benefit to taking Vitamin D supplements in doses below 800 IUs per day for fracture prevention."

Dawson-Hughes and colleagues analyzed each participant's vitamin D supplementation within and independent of the study protocol, controlling for age, vitamin D blood levels at baseline, additional calcium supplementation, and whether the person lived independently or under medical care.

"Evaluation of individual-level data is the gold standard of meta-analysis," says Dr. Heike Bischoff-Ferrari, a visiting scientist in the bone metabolism laboratory who's from the University of Zurich. "Our results make a compelling contribution to the existing data on Vitamin D and fracture risk in men and women age 65 and older, whose vulnerability to bone density loss and osteoporosis leave them prone to fractures resulting from thinning bones."

The current recommended intake of vitamin D set by the Institute of Medicine is a minimum of 600 IUs per day for adults between 51 and 70 years old and 800 IUs in adults older than 70.

"Vitamin D supplementation is an efficient intervention for a costly injury that affects thousands of older adults each year," Dawson-Hughes assert. "The average recovery is long and painful and deeply impacts quality of life. After a fracture, older patients may only regain partial mobility, resulting in a loss of independence that is personally demoralizing and that can place added stress on family members and caregivers."

Financially, Vitamin D supplements cost pennies a day, Dawson-Hughes says, whereas the American Academy of Orthopaedic Surgeons estimated the cost of treating a hip fracture was $26,912 in 2007.

Dawson-Hughes adds that older adults, unless they are exposed to bright, year-round sunlight, require supplementation to meet their vitamin D needs. Typically, adults consume 150 IUs per day from food sources such as tuna or salmon or fortified milk.

On average, multivitamins contain 400 IUs of vitamin D and there are individual vitamin D supplements with 400, 800, or 1,000 IUs.