Do You Qualify

Eligibility

D2d participants will be adults who:

• Are at increased risk for diabetes (also known as “pre-diabetes”) based on blood glucose level following a 75 gram oral glucose tolerance test.
• Are Age 30 years or older.
• Have a Body Mass Index ≥ 25 (23 kg/m² for Asians) ≤ 40 kg/m².
• Are willing to take a daily vitamin D supplement and limit intake outside of the study of multivitamins contanining vitamin D or calcium to the current recommended intakes
• Will be followed for about 4 years for development of diabetes.

D2d participants do not have:

• Diabetes (based on blood glucose levels or use of diabetes-specific medications).
• Recent history of kidney stones or kidney disease.
• Other medical conditions that in the opinion of the site investigators may put the participant at increased risk of harm.

Expectations

• Volunteers that enroll in D2d will be required to take one vitamin D pill or placebo every day with breakfast for about 4 years. Neither participants nor study staff will know who is on vitamin D or placebo.
• During the study, which will last about 4 years, there will be at least 12 visits to the local D2d clinic to test for development of diabetes. Scheduling of visits is flexible and appointments are available Monday through Friday (some D2d clinical sites may be able to see participants on Saturday).