- In a continuing series of disappointing results, vitamin D offers no benefit in preventing type 2 diabetes (T2D) in at-risk people, based on results from a multicenter randomized, placebo-controlled prevention trial.
- Supplementation of 4000 IU/day did not best placebo.
Why this matters
- Based on results of observational studies, vitamin D supplementation was held as potentially protective against several conditions, including T2D and cardiovascular disease, but thus far has largely failed to keep its promise.
- More than 84 million in the United States are at risk for developing T2D, says the American Diabetes Association (ADA).
- Accompanying editorial: results suggest that any benefit is “modest and clearly does not pertain to a vitamin D–sufficient population.”
- After median 2.5-year follow-up:
- With vitamin D: 9.39 diabetes events per 100 person-years.
- With placebo: 10.66 diabetes events per 100 person-years.
- HR for diabetes with vitamin D vs placebo: 0.88 (95% CI, 0.75-1.04; P=.12).
- Adverse events rate did not differ between groups.
- 2423 participants were randomly allocated to vitamin D (n=1211) or placebo (n=1212).
- Mean age was 60.0 years, mean BMI was 32.1, mean HbA1c was 5.9%.
- Funding: NIH, ADA.
- Some differences between nonadherence participants in the groups.