Vitamin D and Type 2 Diabetes Study (D2d)

July 22, 2022 updated by: Tufts Medical Center
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.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

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.

Study Type

Interventional

Enrollment (Actual)

2423

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United States
    • Arizona
      • Phoenix, Arizona, United States, 85016
        • Southwest American Indian Center
    • California
      • Los Angeles, California, United States, 90022
        • University of Southern California
      • Palo Alto, California, United States, 94304
        • Stanford University
    • Colorado
      • Aurora, Colorado, United States, 80045
        • University of Colorado, Denver
    • Florida
      • Orlando, Florida, United States, 32803
        • Orlando VA Medical Center
      • Orlando, Florida, United States, 32804
        • Florida Hospital Translational Research Institute
    • Georgia
      • Decatur, Georgia, United States, 30033
        • Atlanta VA Medical Center
    • Illinois
      • Chicago, Illinois, United States, 60611
        • Northwestern University
    • Kansas
      • Kansas City, Kansas, United States, 66205
        • University of Kansas Medical Center
    • Louisiana
      • Baton Rouge, Louisiana, United States, 70808
        • Pennington Biomedical Research Center
      • New Orleans, Louisiana, United States, 70112
        • Tulane University Health Sciences
    • Maine
      • Scarborough, Maine, United States, 04074
        • Maine Medical Center
    • Maryland
      • Hyattsville, Maryland, United States, 20782
        • MedStar Community Clinical Research Center
    • Massachusetts
      • Boston, Massachusetts, United States, 02111
        • Tufts Medical Center
    • Minnesota
      • Minneapolis, Minnesota, United States, 55454
        • Health Partners Riverside Clinic
    • Nebraska
      • Omaha, Nebraska, United States, 68198
        • University of Nebraska Medical Center
      • Omaha, Nebraska, United States, 68105
        • Omaha VA Medical Center
    • New York
      • New York, New York, United States, 10003
        • Beth Israel Medical Center
    • North Carolina
      • Durham, North Carolina, United States, 27704
        • Duke University
    • Ohio
      • Cleveland, Ohio, United States, 44195
        • Cleveland Clinic
    • Oregon
      • Portland, Oregon, United States, 97227
        • Kaiser Permanente Center for Health Research
    • South Carolina
      • Charleston, South Carolina, United States, 29425
        • Medical University of South Carolina
    • Tennessee
      • Memphis, Tennessee, United States, 38105
        • University of Tennessee Health Science Center
    • Texas
      • Dallas, Texas, United States, 75390
        • University of Texas Southwestern Medical Center
      • Houston, Texas, United States, 77030
        • Baylor College of Medicine

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

30 years and older (ADULT, OLDER_ADULT)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Inclusion Criteria:

  1. Pre-diabetes ("at increased risk for diabetes") defined by meeting 2-out-of-3 of the following glycemic criteria at the baseline visit:

    1. Fasting plasma glucose (FPG) 100-125 mg/dL
    2. 2-hour plasma glucose (2hPG) 140-199 mg/dL
    3. Hemoglobin A1c (HbA1c) 5.7-6.4%
  2. Age ≥ 30 years .(≥25 years for people of the following races: American-Indian, Alaska Native, Native Hawaiian or Other Pacific Islander).
  3. Body Mass Index ≥ 24.0 (22.5 for Asians) and ≤ 42.0 kg/m2
  4. Provision of signed and dated written informed consent prior to any study procedures.

Major Exclusion Criteria:

  1. Diabetes based on either of the following criteria:

    1. 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.
    2. Meeting the diagnosis criteria for diabetes
  2. History (past 3 years) of hyperparathyroidism, nephrolithiasis or hypercalcemia.
  3. 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.
  4. Currently breastfeeding.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: PREVENTION
  • Allocation: RANDOMIZED
  • Interventional Model: PARALLEL
  • Masking: QUADRUPLE

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
PLACEBO_COMPARATOR: Placebo
One pill daily
Other: Placebo
Administered as one soft-gel pill daily by mouth
ACTIVE_COMPARATOR: Vitamin D (Cholecalciferol)
One vitamin D pill daily
Dietary supplement: Vitamin D (Cholecalciferol)
Vitamin D (Cholecalciferol) 4000 IU, administered as 1 soft-gel pill daily by mouth.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Time to Development of Diabetes
Time Frame: Approximately 48 months
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
Time Frame: Approximately 48 months
Approximately 48 months
Variability of Response to Vitamin D Supplementation by Baseline Characteristic: Race (as a Proxy for Skin Pigmentation)
Time Frame: Approximately 48 months
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)
Time Frame: Approximately 48 months
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
Time Frame: Approximately 48 months
Approximately 48 months
Variability of Response to Vitamin D Supplementation by Baseline Characteristic: Waist Circumference
Time Frame: Approximately 48 months
Approximately 48 months
Variability of Response to Vitamin D Supplementation by Baseline Characteristic: Age
Time Frame: Approximately 48 months
Approximately 48 months
Variability of Response to Vitamin D Supplementation by Baseline Characteristic: Geographic Location (as a Proxy for Sun Exposure)
Time Frame: Approximately 48 months
Approximately 48 months
Variability of Response to Vitamin D Supplementation by Baseline Characteristic: Calcium Intake From Supplements
Time Frame: Approximately 48 months
Approximately 48 months
Blood Plasma 25OHD Concentration.
Time Frame: Approximately 48 months
Approximately 48 months
Number of Participants With Adverse Events.
Time Frame: Approximately 48 months
Approximately 48 months
Change in Blood Pressure as a Continuous Variable.
Time Frame: Approximately 48 months
Approximately 48 months
Number of Participants Who Discontinue Study Pills.
Time Frame: Approximately 48 months
Approximately 48 months
Change in FPG as a Continuous Variable.
Time Frame: Every 12 months for approximately 48 months
Every 12 months for approximately 48 months
Change in 2hPG as a Continuous Variable.
Time Frame: Every 12 months for approximately 48 months.
Every 12 months for approximately 48 months.
Change in HbA1c as a Continuous Variable.
Time Frame: Every 6 months for approximately 48 months
Every 6 months for approximately 48 months
Measurement of Insulin Resistance (Derived From the OGTT).
Time Frame: Every 12 months for approximately 48 months
Every 12 months for approximately 48 months
Measurement of Beta Cell Secretion (Derived From the OGTT)
Time Frame: Every 12 months for approximately 48 months
Every 12 months for approximately 48 months
Identification of Characteristics Associated With the Variability in Achieved 25OHD Concentration.
Time Frame: Every 12 months for approximately 48 months
Every 12 months for approximately 48 months

Other Outcome Measures

Outcome Measure
Time Frame
Variability of Response to Vitamin D Supplementation by Baseline Characteristic: Sex
Time Frame: Approximately 48 months.
Approximately 48 months.
Variability of Response to Vitamin D Supplementation by Baseline Characteristic: Ethnicity
Time Frame: Approximately 48 months.
Approximately 48 months.
Variability of Response to Vitamin D Supplementation by Baseline Characteristic: 2 Hour Plasma Glucose
Time Frame: Approximately 48 months
Approximately 48 months
Time to Development of Cancer.
Time Frame: Approximately 48 months.
Approximately 48 months.
Time to Development of Cardiovascular Event.
Time Frame: Approximately 48 months.
Approximately 48 months.
Incidence of Cancer in a Pre-diabetes Population Defined by the Modern American Diabetes Association Criteria.
Time Frame: Approximately 48 months.
Approximately 48 months.
Incidence of Cardiovascular Disease in a Pre-diabetes Population Defined by the Modern American Diabetes Association Criteria.
Time Frame: Approximately 48 months.
Approximately 48 months.
Quality of Life and Mood Scores in Pre-diabetes Population Using a Validated Instrument (PROMIS-29 Profile v2.0 and a General Question on Perception of Overall Health From the PROMIS Scale 1.2).
Time Frame: One time assessment at the month 24 visit.
One time assessment at the month 24 visit.

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Tufts Medical Center

Collaborators

National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
American Diabetes Association
Office of Dietary Supplements (ODS)

Investigators

  • Principal Investigator: Anastassios Pittas, MD, MS, Tufts Medical Center

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

October 1, 2013

Primary Completion (ACTUAL)

November 1, 2018

Study Completion (ACTUAL)

November 1, 2018

Study Registration Dates

First Submitted

August 9, 2013

First Submitted That Met QC Criteria

September 10, 2013

First Posted (ESTIMATE)

September 16, 2013

Study Record Updates

Last Update Posted (ACTUAL)

August 16, 2022

Last Update Submitted That Met QC Criteria

July 22, 2022

Last Verified

July 1, 2022

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • U01DK098245 (NIH)

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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