NCT07448974

Vitamin D and Type 2 Diabetes - Treat-To-Target

Vitamin D and Type 2 Diabetes, Treat-To-Target

• Status: Not Yet Recruiting
• Phase: Phase 3
• Study type: Interventional
• Enrollment: 100 (estimated)
• Sponsor: Tufts Medical Center · Academic / Other
• Sex: All
• Age: 30 Years – 74 Years
• Healthy volunteers: Not accepted

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.

Conditions

• Prediabetes
• Type 2 Diabetes (T2DM)

Interventions

Type	Name	Description
DRUG	Vitamin D (Cholecalciferol )	Vitamin D (cholecalciferol) will be administered orally once weekly for approximately 18 months. The vitamin D will be provided in liquid form in an ampule. Participants in the intervention group will begin with a dose of 25,000 IU per week. A blood vitamin D level will be measured at 3 months, and the dose will be increased to 50,000 IU per week for participants whose results are below the study target.
DRUG	Placebo	Placebo will be administered orally once weekly for approximately 18 months. The placebo will be provided in an ampule and will be matched in appearance, dosing schedule, and duration to the active study medication.

Timeline

• Start date: 2026-05-01
• Primary completion: 2030-03-01
• Completion: 2031-03-01
• First posted: 2026-03-04
• Last updated: 2026-03-05

Locations

1 site across 1 country: United States

Regulatory

• FDA-regulated drug study