Can Vitamin D3 Improve Cognitive Function in Individuals With Type 2 Diabetes? (THINK-D)
Public ClinicalTrials.gov record NCT02416193. 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.
Brief summary
Reproduced verbatim from the official ClinicalTrials.gov record. Not medical advice.
Diabetes increases the risk of cognitive dysfunction. The incidence of dementia is 1.5 to 2.5 times higher in persons with diabetes than the general population. There is evidence that cognitive decline significantly impacts the ability to self-manage diabetes. Strategies to prevent cognitive decline in persons with diabetes has not been well studied. A recent study reported that in persons who had vitamin D deficiency, the risk for all-cause dementia and Alzheimer's was doubled. Vitamin D receptors are located in the brain and deficiency of vitamin D has been reported to negatively affect the development of brain. Therefore, providing vitamin D supplementation to improve cognitive function is worthy of study. The investigators propose a small, randomized controlled trial to determine the effects of vitamin D3 supplementation in persons with type 2 diabetes who have symptoms of cognitive impairment. Persons will be randomized to receive either weekly vitamin D3 supplementation (50,000 IUs) or a matching comparator (5000 IUs) for a period of three months. The study aims are to determine (1) the effect of vitamin D3 supplementation on cognitive function and (2) the effect of vitamin D3 supplementation on diabetes self-management. A sample of persons with type 2 diabetes (n=62), who have a subjective complaint of a cognitive dysfunction or scoring at least one standard deviation below normal on a cognitive functioning screening test, have vitamin D levels less 30 ng/ml, are not depressed (as this impacts cognitive function), and do not have severe diabetes complication will be recruited. Participants will be phone screened and complete two baseline visits prior to randomization. They will then have phone call and follow-up visits to assess (1) cognitive function using standardized tests to assess for executive function (2) serum measurements (HBA1c, fasting glucose, vitamin D levels, and cardiometabolic profile) and (3) surveys to assess cognitive function as well as self-management behaviors.
Study identification
- NCT ID
- NCT02416193
- Recruitment status
- Terminated
- Study type
- Interventional
- Phase
- Phase 2
- Enrollment
- 56 participants
Conditions and interventions
Conditions
Eligibility (public fields only)
- Age range
- 18 Years to 75 Years
- Sex
- All
- Healthy volunteers
- Healthy volunteers not accepted
This page does not interpret eligibility. Detailed inclusion and exclusion criteria are on the official ClinicalTrials.gov record.
Study timeline
- Start date
- Sep 22, 2015
- Primary completion
- Jul 11, 2018
- Completion
- Jul 11, 2018
- Last update posted
- Oct 22, 2020
2015 – 2018
United States locations
- U.S. sites
- 1
- U.S. states
- 1
- U.S. cities
- 1
| Facility | City | State | ZIP | Site status |
|---|---|---|---|---|
| Loyola University Medical Center | Maywood | Illinois | 60153 | — |
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 NCT02416193, 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 Oct 22, 2020 · Synced Sep 9, 2026
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Open the official record
The complete protocol, eligibility criteria, and contact information for NCT02416193 live on ClinicalTrials.gov.