Study of Vitamin D and Omega-3 Supplementation for Preventing Diabetes
Public ClinicalTrials.gov record NCT01633177. Field values are reproduced from the official study page; the official ClinicalTrials.gov record remains the source of truth for eligibility, enrollment, and contact information.
Data is sourced from official ClinicalTrials.gov public API records. Always review the official ClinicalTrials.gov record for the latest information.
Official title
Diabetes Prevention in the Vitamin D and Omega-3 Trial
Brief summary
Reproduced verbatim from the official ClinicalTrials.gov record. Not medical advice.
The VITamin D and OmegA-3 TriaL (VITAL; NCT 01169259) is an ongoing randomized clinical trial in 25,875 U.S. men and women investigating whether taking daily dietary supplements of vitamin D3 (2000 IU) or omega-3 fatty acids (Omacor® fish oil, 1 gram) reduces the risk of developing cancer, heart disease, and stroke in people who do not have a prior history of these illnesses. This ancillary study is being conducted among nondiabetic participants in VITAL and will examine whether vitamin D or fish oil prevent type 2 diabetes. Findings from this ancillary study (n=22220 without diabetes at baseline) conducted within the VITAL trial will clarify whether vitamin D and omega-3 fatty acid supplementation reduces risk of type 2 diabetes and thus will inform public health and clinical guidelines for diabetes prevention.
Study identification
- NCT ID
- NCT01633177
- Recruitment status
- Completed
- Study type
- Interventional
- Phase
- Phase 3
- Enrollment
- 22,220 participants
Conditions and interventions
Conditions
Interventions
- Vitamin D3 Dietary Supplement
- Omega-3 fatty acid (fish oil) Drug
- Vitamin D3 placebo Dietary Supplement
- Fish oil placebo Drug
Dietary Supplement · Drug
Eligibility (public fields only)
- Age range
- 50 Years and older
- Sex
- All
- Healthy volunteers
- Accepts healthy volunteers
This page does not interpret eligibility. Detailed inclusion and exclusion criteria are on the official ClinicalTrials.gov record.
Study timeline
- Start date
- Oct 31, 2011
- Primary completion
- May 29, 2024
- Completion
- May 29, 2024
- Last update posted
- Apr 2, 2026
2011 – 2024
United States locations
- U.S. sites
- 1
- U.S. states
- 1
- U.S. cities
- 1
| Facility | City | State | ZIP | Site status |
|---|---|---|---|---|
| Division of Preventive Medicine, Brigham and Women's Hospital | Boston | Massachusetts | 02215 | — |
Site contact phone numbers, emails, and investigator names are intentionally not displayed here. Open the official ClinicalTrials.gov record for site contact information.
About this trial record page
- What this page shows
- Public field values for ClinicalTrials.gov record NCT01633177, including study identification, conditions, interventions, eligibility (age, sex, healthy volunteer), timeline, and U.S. site list.
- What this page does not do
- No medical advice, eligibility judgments, treatment recommendations, study quality scoring, or AI-generated medical summaries. No site contact phone numbers, emails, or investigator names.
- Where the data comes from
- Sourced from the official ClinicalTrials.gov public API. The official record is the source of truth.
- Last refresh
- Last update posted Apr 2, 2026 · Synced Sep 9, 2026
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Open the official record
The complete protocol, eligibility criteria, and contact information for NCT01633177 live on ClinicalTrials.gov.