NCT00784511

Brief 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. 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.

Trial Health

87
On Track

Trial Health Score

Automated assessment based on enrollment pace, timeline, and geographic reach

Enrollment
100

participants targeted

Target at P50-P75 for phase_2 type-2-diabetes

Timeline
Completed

Started Jul 2008

Longer than P75 for phase_2 type-2-diabetes

Geographic Reach
1 country

1 active site

Status
completed

Health score is calculated from publicly available data and should be used for screening purposes only.

Trial Relationships

Click on a node to explore related trials.

Study Timeline

Key milestones and dates

Study Start

First participant enrolled

July 1, 2008

Completed
4 months until next milestone

First Submitted

Initial submission to the registry

November 3, 2008

Completed
1 day until next milestone

First Posted

Study publicly available on registry

November 4, 2008

Completed
2.2 years until next milestone

Primary Completion

Last participant's last visit for primary outcome

February 1, 2011

Completed
Same day until next milestone

Study Completion

Last participant's last visit for all outcomes

February 1, 2011

Completed
Last Updated

November 14, 2014

Status Verified

November 1, 2014

Enrollment Period

2.6 years

First QC Date

November 3, 2008

Last Update Submit

November 13, 2014

Conditions

Type 2 Diabetes

Keywords

diabetesvitamin DAfrican Americansoverweightinsulin sensitivityglucose control

Outcome Measures

Primary Outcomes (3)

  • Insulin secretion rate

    12 weeks

  • Insulin sensitivity index

    12 weeks

  • 2-hr post load glucose

    12 weeks

Study Arms (2)

1 vitamin D3

EXPERIMENTAL

vitamin D3, 4000 IU/d

Dietary Supplement: cholecalciferol

2

PLACEBO COMPARATOR

placebo

Other: microcrystalline cellulose

Interventions

cholecalciferolDIETARY_SUPPLEMENT

4000 IU/d

Also known as: vitamin D3, vitamin D
1 vitamin D3
microcrystalline celluloseOTHER

1/d

Also known as: placebo
2

Eligibility Criteria

Age40 Years+
Sexall
Healthy VolunteersYes
Age GroupsAdult (18-64), Older Adult (65+)

You may qualify if:

  • 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

You may not qualify if:

  • 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
  • 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
  • +22 more criteria

Contact the study team to confirm eligibility.

Sponsors & Collaborators

Study Sites (1)

Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University

Boston, Massachusetts, 02111, United States

Location

MeSH Terms

Conditions

Diabetes Mellitus, Type 2Diabetes MellitusOverweightInsulin Resistance

Interventions

CholecalciferolVitamin Dmicrocrystalline cellulose

Condition Hierarchy (Ancestors)

Glucose Metabolism DisordersMetabolic DiseasesNutritional and Metabolic DiseasesEndocrine System DiseasesOvernutritionNutrition DisordersBody WeightSigns and SymptomsPathological Conditions, Signs and SymptomsHyperinsulinism

Intervention Hierarchy (Ancestors)

CholestenesCholestanesSteroidsFused-Ring CompoundsPolycyclic CompoundsSterolsSecosteroidsMembrane LipidsLipids

Study Design

Study Type
interventional
Phase
phase 2
Allocation
RANDOMIZED
Masking
QUADRUPLE
Who Masked
PARTICIPANT, CARE PROVIDER, INVESTIGATOR, OUTCOMES ASSESSOR
Purpose
PREVENTION
Intervention Model
PARALLEL
Sponsor Type
OTHER
Responsible Party
PRINCIPAL INVESTIGATOR
PI Title
Scientist I

Study Record Dates

First Submitted

November 3, 2008

First Posted

November 4, 2008

Study Start

July 1, 2008

Primary Completion

February 1, 2011

Study Completion

February 1, 2011

Last Updated

November 14, 2014

Record last verified: 2014-11

Locations

US(1)