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Researching link between vitamin D and diabetes


One is as common as a ray of sunshine; it is also found in many foods you eat every day and can be bought cheaply in pill form at your local pharmacy. The other affects millions of people nationwide and is listed by the Centers for Disease Control and Prevention as the 7th leading cause of death in the United States.

But what do vitamin D and diabetes have to do with each other?

Finding the answer is the subject of exciting new research led by Endocrinologist and Co-Director of the Diabetes Center, Anastassios G. Pittas, MD, MS.

“The best way to approach research is either to find an unusual risk factor or therapy and study it further or take something commonplace and look at it in a different way,” said Pittas. “Our research links two well-established areas in a way that was not previously apparent.”

Pittas’ research on the relationship between vitamin D and type 2 diabetes, in collaboration with Director of the Bone Metabolism Laboratory Bess F. Dawson-Hughes, MD and others outside of Tufts Medical Center, and funded in part by three National Institutes of Health (NIH) grants totaling $3.3 million, has already yielded some groundbreaking results.

Pittas’ studies of healthy women and people with pre-diabetes (those with reduced insulin levels who are at the highest risk for developing type 2 diabetes) have shown an association between higher levels of vitamin D in the blood and a lower future risk of developing type 2 diabetes. His investigations also indicate that vitamin D supplementation improves the body’s ability to produce more insulin and process insulin more efficiently, which may reduce the risk of pre-diabetes patients developing diabetes.

Produced by the pancreas, the hormone insulin removes glucose (sugar) from the bloodstream and facilitates its storage and conversion into energy. People with diabetes either do not produce enough insulin or their body becomes resistant to it. A chronic disease with no known cure, diabetes can lead to potentially life-threatening complications, including stroke, blindness, and diseases of the heart, kidney and nervous system.

Diabetes in the United States

The American Diabetes Association (ADA) reports that diabetes contributed to more than 231,000 deaths nationwide in 2007 and cost the U.S. health care system $174 billion that year. Diabetes currently affects 25.8 million people in the United States; type 2 diabetes accounts for 90 percent of all diabetes cases.

“This research is important because there are currently 79 million people with pre-diabetes in the United States,” said Pittas. “Each of those people has a ten percent chance every year of developing type 2 diabetes. With weight loss and exercise, that risk can be reduced, but lifestyle changes can be hard to achieve and maintain and even if successful, the danger never completely goes away. So, finding additional ways to reduce that possibility would be of great benefit to those at risk for diabetes.”

Still, Pittas cautions that although the evidence linking vitamin D to type 2 diabetes is promising, it is very possible that other variables have contributed to the positive results seen so far. Therefore, he does not recommend taking high doses of vitamin D to prevent type 2 diabetes, until the hypothesis is tested in interventional studies and more definitive data is presented.

That conclusive data might not be too far off. With NIH support, Pittas and his colleagues have prepared and submitted an application to conduct a large interventional study, designed to determine whether vitamin D plays a role in pre-diabetes. The study would be a multi-centered, randomized clinical trial and would include more than 2,000 people at risk for type 2 diabetes. Each participant would receive either vitamin D or placebo and would be followed for up to four years to monitor the effect of vitamin D on the development of type 2 diabetes. Pittas and his team expect to hear if the grant has been accepted for funding by the end of the year.