Individuals at risk for diabetes sought for study of vitamin D

The Stanford University School of Medicine is seeking people at risk for diabetes to participate in a clinical trial to evaluate whether vitamin D supplementation can slow the development of type-2 diabetes.

The study, called D2d, will involve 2,500 participants at 20 sites around the country. The Stanford portion of the trial hopes to recruit 150 participants. The overall study will be the first large clinical trial to test whether dietary supplementation with vitamin D can slow the progression of prediabetes to type-2 diabetes.

Participants should be at least 30 years old and have several risk factors for type-2 diabetes, including higher-than-normal results on fasting glucose and glucose-tolerance tests, as well as a body mass index in the overweight to obese range. For all eligibility criteria, visit http://www.d2dstudy.org.

Those interested in participating should contact study coordinator Josephine Hau at (650) 723-1301 or jhau@stanford.edu. The initial screening process will include a questionnaire, which is available at http://www.d2dstudy.org/stanford.

The principal investigator of the Stanford portion of D2d is Sun Kim, MD, assistant professor of endocrinology. Christopher Gardner, PhD, associate professor of medicine, is a co-investigator.

Study participants will take 4,000 international units of vitamin D per day, which is above the typical intake of 600-800 IU but considered safe based on other studies. Participants randomized to the control group will receive a placebo. Glucose tolerance will be monitored every year to test for progression to type-2 diabetes. The study is expected to continue for about four years, or until enough participants have developed diabetes to gauge the effect of vitamin D.

Vitamin D helps the body absorb calcium and is important for the functioning of bones, nerves, muscles and the immune system. Because the body needs sunlight to synthesize vitamin D, recent increases in vitamin D deficiency may be due in part to skin-cancer-prevention recommendations to limit sun exposure. Population-level studies have shown associations between low levels of vitamin D and type-2 diabetes, autoimmune diseases and cancer. But more research is needed to determine whether increasing vitamin D levels can help prevent such diseases.

Participants in the study will receive a thorough evaluation of their risk for diabetes, which is not available through routine clinical practice. Medical examination and testing results will be available at no cost. Participants will also be kept abreast of up-to-date information on diabetes prevention and may receive up to $270 in compensation over four years.

D2d (ClinicalTrials.gov number NCT01942694) is supported under the National Institutes of Health grant U01DK098245. The National Institute of Diabetes and Digestive and Kidney Diseases is the primary sponsor of the trial, with additional support from the NIH Office of Dietary Supplements and the American Diabetes Association. Support in the form of educational materials is provided by the National Diabetes Education Program.