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In the News: Vitamin D Trials in Progress: Prevention of Diabetes, CVD, Cancer, AMD?

Can Vitamin D & Omega-3s Prevent AMD: VITAL

When the Institute of Medicine released its report recommending an increase in the RDA for vitamin D in 2010, the IOM panel concluded that the evidence is clear that vitamin D has bone benefits but that current research is inconclusive as to whether higher vitamin D intake can cut the risk for cancer, heart disease, stroke, or other chronic diseases.

In response to this uncertainty, the ongoing VITAL (VITamin D3 and OmegA-3 TriaL)1 was initiated by researchers at Brigham and Women’s Hospital, an affiliate of Harvard Medical School, and Harvard’s School of Public Health.

This large-scale 2×2 factorial trial is designed to test whether vitamin D3 (cholecalciferol, 2000 IU/day) and marine omega-3 fatty acids (EPA +DHA, 1 g/day) can prevent cancer and cardiovascular disease in people without a prior history of these illnesses.

VITAL is enrolling a multi-ethnic population of more than 25,000 U.S. men aged ≥50 and women aged ≥55. More than 24,000 participants have been enrolled to date. 

In addition to the primary endpoints, over a dozen sub-studies are testing the effect of vitamin D and fish oil on other health outcomes such as cognitive function, diabetes-related kidney disease, and age-related macular degeneration (AMD).  

Several studies have found a relationship between vitamin D and AMD. The most recent of these reports an association of higher serum levels of vitamin D with a reduced risk of developing early AMD among women under 75 years of age.  

Current plans are for an average treatment and follow-up of approximately 5 years for VITAL participants. Thus, in the near future, we should have reliable data to evaluate whether vitamin D (and EPA + DHA) have a role in the primary prevention of AMD as well as other chronic diseases.

Can Vitamin D Protect Against Diabetes: D2d Trial

Tufts Medical Center researchers have received a large NIH grant to examine whether vitamin D supplements can help to prevent or delay the onset of Type 2 diabetes in adults with pre-diabetes – blood glucose levels that are higher than normal but not yet high enough to be diagnosed as diabetes. Approximately 79 million Americans have pre-diabetes.

Called the D2d Trial (Vitamin D and Type 2 Diabetes)2, it will be the first study to definitively answer whether vitamin D3 (4,000 IU daily) can reduce the risk of developing diabetes.

The trial aims to recruit about 2.500 people over 30 years of age, and will be conducted at approximately 20 medical centers countrywide. D2d has been launched and recruitment is underway.

Past observational studies suggest that higher vitamin D levels may be protective against Type 2. Based on these studies, it’s estimated that vitamin D could reduce diabetes risk by about 25%. Preliminary research by Tufts investigators has also found that vitamin D can improve blood glucose levels in those at increased risk for the disease.   

A positive outcome of the D2d study would mean an affordable and accessible way to help reduce the health care burdens of this disease, including complications such as diabetic retinopathy. Up to 21% of patients with type 2 have retinopathy at the time of first diagnosis of diabetes, and most develop some degree of retinopathy over time.

References

1. Manson JE et al. The VITamin D and omegA-3 triaL (VITAL): Rationale and design of a large randomized controlled trial of vitamin D and marine omega-3 fatty acid supplements for the primary prevention of cancer and cardiovascular disease. Contemp Clin Trials 33:159-71, 2012.
2. www.D2dstudy.org