The meta-analysis – published in the New England Journal of Medicine – pooled data from over 31,000 people in 11 randomised clinical trials that looked into the possible benefits of vitamin D supplementation for the reduction of fracture risk.
Led by vitamin D expert, Professor Bischoff-Ferrari from the University of Zurich, Switzerland, the research team found those taking high doses of vitamin D – between 800 and 2,000 International Units (IUs)– sustained 30% fewer hip fractures in addition to 14% less fractures of other bones, when compared to the control groups.
“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 makes leave them prone to fractures resulting from thinning bones,” said the vitamin D expert.
Professor Bess Dawson-Hughes, senior author of the study, added: “Taking between 800 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.”
“Importantly we saw there was no benefit to taking vitamin D supplements in doses below 800 IUs per day,” she added.
Dawson-Hughes added that supplementation with vitamin D is an efficient intervention for a problem that can be costly. She noted that supplements cost pennies whereas the estimated cost of treating a fracture is thousands.
"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"
Bischoff-Ferrari and her colleagues analysed 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," she noted.
The team divided the subjects into quartiles ranging from 0 to 2,000 International Units (IUs) of daily vitamin D intake.
In the top quartile, there was a 30% reduction in hip fracture risk and a 14% reduced risk of fracturing other bones, compared to the control groups.
Dawson-Hughes said the results of the current study would be strengthened by large interventional trials investigating the impact of vitamin D supplementation on fracture risk.
The research team also called for further investigation of the impact of combining calcium supplementation with high doses of vitamin D, as their data was inconclusive.
Source: New England Journal of Medicine
Volume 367, Pages 40-49, doi: 10.1056/NEJMoa1109617
“A Pooled Analysis of Vitamin D Dose Requirements for Fracture Prevention”
Authors: H.A. Bischoff-Ferrari, et al.