We are testing whether adjusting vitamin D doses to reach a target vitamin D blood level can improve blood sugar control in adults with high-risk prediabetes. Adults at risk for type 2 diabetes will be randomly assigned to receive vitamin D3 or a placebo once a week for 18 months. After three months, vitamin D levels will be checked, and the dose may be increased if the target level isn’t reached. Neither participants nor the research team will know who is receiving vitamin D or placebo. At study visits, participants will have blood and urine samples collected, have a continuous glucose monitor applied, complete questionnaires, and review their medical history, medication use, and any changes over time. Visits occur every six months, with short phone check-ins in between.
D2d-TTT
Vitamin D and type 2 diabetes – Treat-To-Target
Pre-diabetes
All genders
18-74
Recruiting now
Overview
Principal Investigator: Anastassios Pittas
Contact Us
Elise Danico/ Endocrinology Research
Study details
Inclusion Criteria
- High-risk prediabetes. Both criteria must be met:
a. Fasting blood sugar between 100 and 125 mg/dL
b. Hemoglobin A1c (a measure of average blood sugar) between 5.7% and 6.4% - Body mass index (BMI) must be between 23.0 and 35.0 kg/m²
Exclusion Criteria
- Prior history of diabetes.
- Currently taking medications approved for weight management (such as Ozempic, Zepbound) or plan to start them during the study.
- Have taken vitamin D supplements over 1000 IU/day within 8 weeks of the first study visit, or calcium supplements over 600 mg/day within 1 week of the first visit, and are not willing to limit these supplements to below those amounts during the study (supplements include products like cod liver oil.)
Study Requirements
There will be six study visits over the course of 18 months plus two interim phone calls. Follow up visits take place approximately every 6 months. At study visits, participants will have blood and urine samples collected, have a continuous glucose monitor applied, complete questionnaires, and review their medical history, medication use, and any changes over time.