Summary
background
Vitamin D supplements are widely recommended for bone health in the general population, but data on whether they prevent fractures have been inconsistent.
methods
Download a PDF of the research summary.
In an ancillary study of the Vitamin D and Omega-3 Trial (VITAL), we tested whether supplemental vitamin D3 would lead to a lower risk of fractures than placebo. VITAL was a double-blind, randomized, factorial, controlled trial that investigated whether supplemental vitamin D3 (2,000 IU per day), n−3 fatty acids (1 g per day), or both could prevent cancer and disease cardiovascular disease in men 50 years and older and women 55 years and older in the United States. Participants were not recruited on the basis of vitamin D deficiency, low bone mass, or osteoporosis. Incident fractures were reported by participants in annual questionnaires and adjudicated by centralized review of medical records. The primary endpoints were total, nonvertebral, and incident hip fractures. Proportional hazards models were used to estimate the treatment effect in the intention-to-treat analyses.
results
Among 25,871 participants (50.6% women [13,085 of 25,871] and 20.2% black [5106 of 25,304]), we confirmed incident fractures from 1991 in 1551 participants during a mean follow-up of 5.3 years. Supplemental vitamin D3, compared with placebo, had no significant effect on total fractures (which occurred in 769 of 12,927 participants in the vitamin D group and in 782 of 12,944 participants in the placebo group; hazard ratio, 0.98, 95% confidence interval [CI], 0.89 to 1.08; P = 0.70), nonvertebral fractures (hazard ratio, 0.97; 95% CI, 0.87 to 1.07; P = 0.50), or hip fractures (hazard ratio, 1.01 ; 95% CI, 0.70 to 1.47; P = 0.96). There was no treatment effect modification by baseline characteristics such as age, sex, race or ethnicity, body mass index, or serum 25-hydroxyvitamin D levels. No there were substantial between-group differences in adverse events assessed in the parent trial.
Conclusions
Vitamin D3 supplementation did not result in a significantly lower risk of fractures than placebo among generally healthy middle-aged adults and older adults who were not screened for vitamin D deficiency, low bone mass, or osteoporosis. (Funded by the National Institute of Arthritis and Musculoskeletal and Skin Diseases; VITAL ClinicalTrials.gov number, NCT01704859.)
QUICK VIDEO SUMMARY Vitamin D and fracture risk among adults 01:47