Vitamin D and Type 2 Diabetes - Treat-To-Target (NCT07448974) | Clinical Trial Compass
Not Yet RecruitingPhase 3
Vitamin D and Type 2 Diabetes - Treat-To-Target
United States100 participantsStarted 2026-05
Plain-language summary
This study tests whether taking a weekly dose of vitamin D, with the dose adjusted to reach a target blood vitamin D level, can help control blood sugar levels in adults at high risk of developing type 2 diabetes (prediabetes).
Research suggests that vitamin D may play a role in blood sugar control. The goal of this study is to see whether adjusting the dose of vitamin D to reach a specific blood vitamin D level improves blood sugar control compared with a placebo (a look-alike pill without vitamin D).
One hundred adults aged 30 to 74 with prediabetes will take part. Participants will be randomly assigned (by chance) to receive either weekly vitamin D supplements or a placebo. Neither the participants nor the research team will know which group a participant is in during the study.
Participants in the vitamin D group will start with one specific dose. After three months, a blood test will be used to decide whether the dose should stay the same or be increased to reach the target vitamin D level. Participants in the placebo group will continue taking the placebo each week.
All participants will be followed for about 18 months. During the study, they will attend scheduled study visits, have blood tests, and wear a continuous glucose monitor, a small device that measures blood sugar levels throughout the day and night. The research team will also make periodic phone calls to check on health changes, medication use, and study participation.
The main outcome of the study is the proportion of time that the participants' blood sugar levels remains in a healthy range.
Who can participate
Age range30 Years – 74 Years
SexALL
See this in plain English?
AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.
Inclusion criteria
✓. High-risk prediabetes ("at high risk for type 2 diabetes") defined by meeting the following 2 prediabetes criteria established by the American Diabetes Association (ADA) in the 2010 clinical practice guidelines:
✓. Provision of signed and dated written informed consent prior to any study procedures.
Exclusion criteria
✕. History of diabetes (ICD10 diabetes code E08.X through E13.X) or meeting a diabetes glycemic criterion at screening, as defined by the ADA guidelines (FPG ≥ 126 mg/dL or HbA1c ≥ 6.5%).
✕. History (past 2 years) of hyperparathyroidism, symptomatic or asymptomatic (i.e., radiographic) nephrolithiasis or hypercalcemia.
✕. Any medical condition (past 2 years) that in the opinion of the site investigator may increase risk for nephrolithiasis or hypercalcemia during the trial (e.g., sarcoidosis).
What they're measuring
1
Time-in-normoglycemia 140
Timeframe: Assessed every 6 months from enrollment to the end of the study at 18 months.
2
Time-In-Normoglycemia 126
Timeframe: Assessed every 6 months from enrollment to the end of the study at 18 months.
✕. If older than 70 years, history (past 1 year) of a fall.
✕. Use of tanning devices within 12 weeks of the baseline visit and unwilling to stop use of tanning devices for the duration of the study.
✕0. Use (past 6 months) of hypoglycemic pharmacotherapy (oral or injectable medication approved by the FDA for type 2 diabetes) for any condition (e.g., prediabetes, diabetes, polycystic ovarian syndrome, MASLD, sleep apnea) or any other medication that may affect glycemia (e.g., hydroxychloroquine)
✕1. Current use of medications approved by the FDA for weight management (e.g., incretin receptor agonists) or planned use during the study.
✕2. Use of supplements containing vitamin D at total doses higher than 1000 IU/day within 8 weeks of the baseline visit and unwillingness to limit vitamin D supplementation dosage to no higher than 1000 IU/day during the study. Because supplements vary widely in vitamin D content (e.g., may include cod liver or cod liver oi), participants will bring all supplements to the site for a review by the research team.