Vitamin D in Minorities With Prediabetes

Study Overview
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Brief Summary
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Vitamin D supplementation in minority subjects with both pre-diabetes and low vitamin D levels will delay the development of diabetes.

Detailed Description
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Low vitamin D levels 1) are associated with abnormalities in insulin secretion and insulin action, 2) predict the development of diabetes in those without diabetes, and 3) are more common in people with diabetes. Minority populations (African-Americans and Latinos) are more likely to have both low levels of vitamin D and diabetes. This study will identify minority individuals who are at increased risk for diabetes (those with central obesity, family history of diabetes in first degree relatives and either with hypertension or being treated for hypertension), and determine if they have both pre-diabetes, ie, impaired fasting glucose and/or impaired glucose tolerance, and low levels of vitamin D. Those that have both will be randomized to either high doses of vitamin D or placebo and insulin secretion and action as well as changes in the oral glucose tolerance test (reversion to normal, maintenance of pre-diabetes or development of diabetes) will be monitored at 3 month intervals for one year. This study will test the hypothesis that the increased amount of diabetes in minority populations may be due in part to low levels of vitamin D and whether supplementing this vitamin may delay the development of diabetes.

Official Title
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Effect of Vitamin D Supplementation on Pre-Diabetes in a Minority Population

Conditions
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Pre-diabetes

Intervention / Treatment
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* Drug: vitamin D
* Drug: placebo


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age greater than 40. Impaired fasting glucose (FPG level greater than 100 and less than 126 mg/dl); and/or Impaired glucose tolerance (2-h plasma glucose concentration after 75 gram glucose load greater than 140 and less than 200 mg/dl) Serum 25-OHD less than 30 ng/ml Able and willing to provide informed consent Exclusion Criteria: FPG greater than 126 mg/dl or 2-hour-OGTT plasma glucose greater than 200 mg/dl Major psychiatric disorder on medication (excluding successfully treated depression) Diagnosed diabetes mellitus HIV/AIDS Major hematological, hepatic (AST/ALT levels greater than or equal to 2 times normal) or renal eGFR less than 60 ml/min) disorder History of carcinoma, except skin basal cell or squamous cell skin carcinomas Heart failure, unstable angina or history of a myocardial infarction Alcohol or substance abuse Current treatment with glucocorticoids Current treatment with diabetes medications, including metformin Cushing's syndrome Primary hyperparathyroidism Nephrolithiasis Pregnancy or breast-feeding Regular visits to a tanning salon (unlikely in this minority population)

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 90 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Prevention
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Placebo Comparator: Placebo<br>Subjects with low vitamin D levels and pre-diabetes | Drug: placebo<br>* medium chain triglyceride given once per week<br>|
| Experimental: vitamin D<br>Subjects with low vitamin D levels and pre-diabetes | Drug: vitamin D<br>* liquid vitamin D3 dissolved in medium chain triglyceride once a week<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Percent of Subjects Who Develop Diabetes | Diabetes defined by a FPG>=126 mg/dl or a 2-hr glucose concentration on an OGTT of >=200 mg/dl | one year | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Disposition Index | Measure of insulin secretion multiplied by measure of insulin sensitivity,both derived from oral glucose tolerance test; higher values are better | Baseline, 3, 6, 9, 12 months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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pre-diabetes, minorities, oral glucose tolerance test, disposition index, insulin secretion, insulin sensitivity, diabetes