Type 2 DiabetesPhase 2NCT00784511
Vitamin D, Glucose Control and Insulin Sensitivity in African-Americans
A Phase 2 study testing cholecalciferol and microcrystalline cellulose in people with Type 2 Diabetes, run by Tufts University at 1 site in United States.
Trial summary
North American blacks tend to have low blood levels of vitamin D because pigmentation blocks vitamin D production in the skin. They also have higher rates of developing type 2 diabetes and higher rates of complications from the disease compared with whites. Read more about this study
- Who is it for?
- Ages 40 years and olderHealthy volunteers can take part
- Conditions the study is for
- Type 2 Diabetes
- What is being tested?
- cholecalciferol and microcrystalline cellulose
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 100 participants
- Where
- 1 siteUnited States
- Study dates
- Jul 2008to Feb 2011
- Phase
- Phase 2
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 40 years and older
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- African-American by self designation
- Glucose intolerance defined as FPG ≥ 100 mg/dl or A1c ≥ 5.8%
- BMI 25.0-39.9
- Age 40 or older
Who cannot join
- Medical Conditions
- Diabetes potentially requiring pharmacotherapy, defined as A1c > 7%
- Uncontrolled thyroid disease
- Current parathyroid, liver or kidney disease
- Renal stone within 5 years
- Sarcoidosis, current pancreatitis, active tuberculosis, hemiplegia, gout
Show all 37Show fewer
- Inflammatory bowel disease, colostomy, malabsorption
- Cancer other than basal cell skin cancer within 5 years
- Uncontrolled arrhythmia in past year
- Albinism or other condition associated with reduced skin pigmentation
- Pregnancy over the last 1 year
- Intent to become pregnant
- Menopause onset within 1 year
- Any other unstable medical condition Laboratory Tests
- Fasting plasma glucose < 100
- Hemoglobin A1c > 7%
- Laboratory evidence of liver disease (e.g. AST > 70 U/L or ALT > 72 IU/L)
- Laboratory evidence of kidney disease (e.g. estimated glomerular filtration rate < 60 ml/min/1.73 m2).
- Elevated spot urine calcium to creatinine ratio > 0.38 mg/dl*
- Abnormal serum calcium (serum calcium > 10.5 mg/dl)
- Anemia (Hematocrit < 36% in men, <33% in women) Medications (use in past three months)
- Estrogen or testosterone
- Prescription vitamin D
- Lithium
- Oral corticosteroids
- Anti-seizure medications
- Unstable doses of psychotropics or phenothiazines
- Cholestyramine Supplements (current use - may discontinue after screening)
- Vitamin D supplements, cod liver oil, calcium supplements Other
- Body mass index less <25 or > 39.9
- Consumption of more than 14 alcoholic drinks per week
- Inability to attend all three study visits as scheduled
- Inability to provide written informed consent
- age < 40 years
- not African-American (by self-designation)
- Participation in another research intervention study
- corresponds to a 24-hour urinary calcium excretion > 400 mg
Trial locations and contacts
1 site in 1 country.
United States1 site
Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University
Boston, Massachusetts, 02111
About this study
North American blacks tend to have low blood levels of vitamin D because pigmentation blocks vitamin D production in the skin. They also have higher rates of developing type 2 diabetes and higher rates of complications from the disease compared with whites. Although there is compelling evidence that adequate vitamin D may reduce the risk for type 2 diabetes in whites, recent evidence from a national survey demonstrated an association of vitamin D with diabetes in whites but not in blacks. However, the central hypothesis of this study is that providing enough supplemental vitamin D to blacks (raising their blood levels higher than that of most participants in the survey) will improve blood measures related to diabetes risk. The proposed study is a 12-week randomized, double-blind, placebo-controlled experiment designed to examine the effect of vitamin D supplementation (100 μg/d ) on insulin secretion, insulin sensitivity and glucose control in pre-diabetic black men and women aged 40 and older.
- Conditions
- Type 2 Diabetes
- Being tested
- cholecalciferol, microcrystalline cellulose
- Keywords
- diabetes, vitamin D, African Americans, overweight, insulin sensitivity, glucose control
- Medical subject headings
- Diabetes Mellitus, Type 2, Diabetes Mellitus, Overweight, Insulin Resistance
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
cholecalciferolDietary supplement
Also called vitamin D3, vitamin D
4000 IU/d
microcrystalline celluloseOther
Also called placebo
1/d
| Study group | Role | What they receive |
|---|---|---|
| 1 vitamin D3 | Experimental | vitamin D3, 4000 IU/d Receives: Dietary Supplement: cholecalciferol |
| 2 | Placebo comparator | placebo Receives: Other: microcrystalline cellulose |
What is being measured
The primary outcome is the main question the study is designed to answer.
Insulin secretion rate
Measured: 12 weeks
Insulin sensitivity index
Measured: 12 weeks
2-hr post load glucose
Measured: 12 weeks
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted4 Nov 2008 (estimated)
- Study startJul 2008
- Primary completionFeb 2011
- Study completionFeb 2011
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Type 2 DiabetesStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 2
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Quadruple blind
- Who is masked
- Participant, Care provider, Investigator, Outcomes assessor
- Enrolment
- 100 participants (actual)
Sponsor and investigators
- Lead sponsor
- Tufts University
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Susan Harris, Tufts University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT00784511
- Sponsor's protocol ID
- 8095
- Other IDs
- ADA 7-08-CR-27
- Status last verified
- Nov 2014
- First submitted
- 3 Nov 2008
- Last updated
- 14 Nov 2014
- Results posted
- No
- Data monitoring committee
- No
Study at a glance
From the registry record, last updated by the sponsor on 14 Nov 2014. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Vitamin D, Glucose Control and Insulin Sensitivity in African-Americans
- ClinicalTrials.gov ID
- NCT00784511
- Acronym / sponsor ID
- 8095
- Conditions
- Type 2 Diabetes
- Keywords
- diabetes, vitamin D, African Americans, overweight, insulin sensitivity, glucose control
- Phase
- Phase 2
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 100 participants (actual)
- Lead sponsor
- Tufts UniversityUniversity, hospital or other
- Study start
- Jul 2008
- Primary completion
- Feb 2011 (actual)
- Study completion
- Feb 2011 (actual)
- First posted
- 4 Nov 2008 (estimated)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
North American blacks tend to have low blood levels of vitamin D because pigmentation blocks vitamin D production in the skin. They also have higher rates of developing type 2 diabetes and higher rates of complications from the disease compared with whites. Although there is compelling evidence that adequate vitamin D may reduce the risk for type 2 diabetes in whites, recent evidence from a national survey demonstrated an association of vitamin D with diabetes in whites but not in blacks. However, the central hypothesis of this study is that providing enough supplemental vitamin D to blacks (raising their blood levels higher than that of most participants in the survey) will improve blood measures related to diabetes risk. The proposed study is a 12-week randomized, double-blind, placebo-controlled experiment designed to examine the effect of vitamin D supplementation (100 μg/d ) on insulin secretion, insulin sensitivity and glucose control in pre-diabetic black men and women aged 40 and older.
Study design
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Quadruple blind (participant, care provider, investigator, outcomes assessor)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| 1 vitamin D3 | Experimental | Dietary Supplement: cholecalciferolvitamin D3, 4000 IU/d |
| 2 | Placebo comparator | Other: microcrystalline celluloseplacebo |
Who may qualify
- Ages
- 40 years and older
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (4 listed)
- African-American by self designation
- Glucose intolerance defined as FPG ≥ 100 mg/dl or A1c ≥ 5.8%
- BMI 25.0-39.9
- Age 40 or older
Key exclusion criteria (37 listed)
- Medical Conditions
- Diabetes potentially requiring pharmacotherapy, defined as A1c > 7%
- Uncontrolled thyroid disease
- Current parathyroid, liver or kidney disease
- Renal stone within 5 years
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| cholecalciferolAlso: vitamin D3, vitamin D4000 IU/d | Dietary supplement | 1 vitamin D3 |
| microcrystalline celluloseAlso: placebo1/d | Other | 2 |
Primary outcome
Insulin secretion rate
Time frame: 12 weeks
Insulin sensitivity index
Time frame: 12 weeks
2-hr post load glucose
Time frame: 12 weeks
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 14 Nov 2014.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 2 study testing cholecalciferol and microcrystalline cellulose in people with Type 2 Diabetes, run by Tufts University at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 4 inclusion and 37 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 14 Nov 2014. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Insulin secretion rate (time frame: 12 weeks). The study lists 3 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 14 Nov 2014.