Vitamin D and Type 2 Diabetes Study

Study Overview
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Brief Summary
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The goal of the Vitamin D and type 2 diabetes (D2d) study is to determine if vitamin D supplementation works to delay the onset of type 2 diabetes in people at risk for the disease and to gain a better understand how vitamin D affects glucose (sugar) metabolism.

Detailed Description
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The goal of the Vitamin D and type 2 diabetes (D2d) study is to determine if vitamin D supplementation works to delay the onset of type 2 diabetes in people at risk for the disease and to gain a better understand how vitamin D affects glucose (sugar) metabolism. Researchers at US sites will enroll people with pre-diabetes (people who have higher than normal blood glucose level but not high enough to meet the diagnosis of diabetes). The study will enroll participants over approximately 2 years and participants will be followed for approximately 3 years. Participants will receive either Vitamin D or a placebo by chance. Participants will take 1 pill a day for the duration of the study.

Official Title
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Vitamin D and Type 2 Diabetes Study

Conditions
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Prediabetes, Type 2 Diabetes

Intervention / Treatment
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* Dietary Supplement: Vitamin D (Cholecalciferol)
* Other: Placebo


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Pre-diabetes (at increased risk for diabetes) defined by meeting 2-out-of-3 of the following glycemic criteria at the baseline visit: Fasting plasma glucose (FPG) 100-125 mg/dL 2-hour plasma glucose (2hPG) 140-199 mg/dL Hemoglobin A1c (HbA1c) 5.7-6.4% Age ≥ 30 years .(≥25 years for people of the following races: American-Indian, Alaska Native, Native Hawaiian or Other Pacific Islander). Body Mass Index ≥ 24.0 (22.5 for Asians) and ≤ 42.0 kg/m2 Provision of signed and dated written informed consent prior to any study procedures. Major Exclusion Criteria: Diabetes based on either of the following criteria: History (past 1 year) of hypoglycemic pharmacotherapy (oral or injectable medication approved by the FDA for type 2 diabetes), used for any condition (e.g. pre-diabetes, diabetes, polycystic ovarian syndrome. Meeting the diagnosis criteria for diabetes History (past 3 years) of hyperparathyroidism, nephrolithiasis or hypercalcemia. Pregnancy (past 1 year by report or positive pregnancy test at screening), intent to become pregnant in the next 4 years or unprotected intercourse. History of gestational diabetes is not an exclusion criterion. Currently breastfeeding.

Ages Eligible for Study
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Minimum Age: 30 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: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Placebo Comparator: Placebo<br>One pill daily | Other: Placebo<br>* Administered as one soft-gel pill daily by mouth<br>|
| Active Comparator: Vitamin D (Cholecalciferol)<br>One vitamin D pill daily | Dietary Supplement: Vitamin D (Cholecalciferol)<br>* Vitamin D (Cholecalciferol) 4000 IU, administered as 1 soft-gel pill daily by mouth.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Time to Development of Diabetes | New-onset diabetes was based on annual glycemic testing of fasting plasma glucose, glycated hemoglobin, and 2-hour post-load plasma glucose and semiannual testing of fasting plasma glucose and glycated hemoglobin. If two or three of the glycemic measures met the 2010 ADA thresholds for diabetes, the participant was considered to have met the diabetes outcome. When only the measure for fasting plasma glucose or glycated hemoglobin met the threshold, confirmatory testing was performed for the positive measure within 8 weeks. If only the measure for 2-hour post-load plasma glucose met the threshold, then a 75-g oral glucose tolerance test to reassess all three glycemic measures was repeated. If the repeat measure was positive or both fasting plasma glucose and glycated hemoglobin were positive (in the case of a repeat oral glucose tolerance test), than the participant was considered to have met the diabetes outcome. | Approximately 48 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Variability of Response to Vitamin D Supplementation by Baseline Characteristic: 25OHD Concentration |  | Approximately 48 months | 
| Variability of Response to Vitamin D Supplementation by Baseline Characteristic: Race (as a Proxy for Skin Pigmentation) | Race and ethnic group were reporting by the participant. The category other includes American Indian or Alaska Native; Native Hawaiian or other Pacific Islander; and other race. Ethnic group includes any race. | Approximately 48 months | 
| Variability of Response to Vitamin D Supplementation by Baseline Characteristic: Pre-diabetes Criteria (Two vs. Three Criteria) | Participants met at least two of three glycemic criteria for prediabetes: fasting plasma glucose level, 100 to 125 mg per deciliter (5.6 to 6.9 mmol per liter); plasma glucose level 2 hours after a 75-g oral glucose load, 140 to 199 mg per deciliter (7.8 to 11.0 mmol per liter) (impaired glucose tolerance); and glycated hemoglobin level, 5.7 to 6.4% (39 to 47 mmol per mole). | Approximately 48 months | 
| Variability of Response to Vitamin D Supplementation by Baseline Characteristic: BMI |  | Approximately 48 months | 
| Variability of Response to Vitamin D Supplementation by Baseline Characteristic: Waist Circumference |  | Approximately 48 months | 
| Variability of Response to Vitamin D Supplementation by Baseline Characteristic: Age |  | Approximately 48 months | 
| Variability of Response to Vitamin D Supplementation by Baseline Characteristic: Geographic Location (as a Proxy for Sun Exposure) |  | Approximately 48 months | 
| Variability of Response to Vitamin D Supplementation by Baseline Characteristic: Calcium Intake From Supplements |  | Approximately 48 months | 
| Blood Plasma 25OHD Concentration. |  | Approximately 48 months | 
| Number of Participants With Adverse Events. |  | Approximately 48 months | 
| Change in Blood Pressure as a Continuous Variable. |  | Approximately 48 months | 
| Number of Participants Who Discontinue Study Pills. |  | Approximately 48 months | 
| Change in FPG as a Continuous Variable. |  | Every 12 months for approximately 48 months | 
| Change in 2hPG as a Continuous Variable. |  | Every 12 months for approximately 48 months. | 
| Change in HbA1c as a Continuous Variable. |  | Every 6 months for approximately 48 months | 
| Measurement of Insulin Resistance (Derived From the OGTT). |  | Every 12 months for approximately 48 months | 
| Measurement of Beta Cell Secretion (Derived From the OGTT) |  | Every 12 months for approximately 48 months | 
| Identification of Characteristics Associated With the Variability in Achieved 25OHD Concentration. |  | Every 12 months for approximately 48 months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Prediabetes, Vitamin D