A research team led by Anastassios G. Pittas, MD, MS, Endocrinologist and Co-Director of the Diabetes Center at Tufts Medical Center in Boston, has received a National Institutes of Health (NIH) grant of more than $40 million over five years to conduct the Vitamin D and Type 2 diabetes (D2d) study.* D2d is a nationwide clinical trial to determine if vitamin D supplementation can reduce the likelihood of developing type 2 diabetes in people who are at high risk for this serious metabolic disorder.

Despite a lack of conclusive evidence to the effectiveness of vitamin D for conditions not related to bone health, sales of vitamin D supplements in the United States have skyrocketed to $425 million annually, making it one of the top selling supplements in the country and one of the most talked about topics in health and medicine. The D2d study, which is coordinated out of the Division of Endocrinology at Tufts Medical Center, is the first of its kind to specifically examine whether vitamin D has an effect on prevention of type 2 diabetes.

"Early studies, by our team and others, suggest a strong link between vitamin D and reduction of diabetes risk," said Pittas, who has investigated the connection since 2002. "While there is a lot of hype about vitamin D and its health benefits, including for diabetes, there is not yet enough evidence from clinical trials to support a recommendation of vitamin D supplementation for diabetes prevention. If the D2d study confirms our hypothesis, it could have a significant impact on the quality of life for millions of people and could potentially save the American health care system billions of dollars."

According to the Centers for Disease Control and Prevention, diabetes is the 7th-leading cause of death in the United States, responsible for more than 69,000 fatalities in 2010. A chronic disease with no known cure, diabetes also can lead to other severe health complications, including stroke, blindness, and diseases of the heart, kidney and nervous system. Data from the 2011 National Diabetes Fact Sheet indicates that nearly 26 million Americans are currently living with the disease; 79 million more (about one-third of the adult U.S. population) are at a high risk for developing type 2 diabetes. The American Diabetes Association estimates that diabetes cost the U.S. health care system approximately $245 billion in 2012.

"Maintaining a healthy diet and staying physically active is the best way to lower the risk of type 2 diabetes," said Pittas. "However, achieving and maintaining the required lifestyle changes long-term is a challenge for many people. Therefore, it is critical to find new preventive measures that are safe, effective, affordable and easily applied to prevent future type 2 diabetes cases."

About 2,500 people at high risk for diabetes will be recruited for this landmark trial, which will take place at 20 medical centers in 17 different states across the country. Participants will receive either vitamin D supplementation or placebo, and will be followed for development of diabetes twice a year for approximately four years. Results of the D2d study are expected in 2018.

"At the completion of the study, our goal is to have conclusive evidence as to whether vitamin D supplementation lowers the risk of diabetes," said D2d Project Manager Patricia Sheehan, RN, MPH, MS. "The first step in reaching this objective is encouraging people at high risk for diabetes to take part in this important clinical trial."