VitDmet: Glucose Metabolism Effects of Vitamin D Supplementation in Prediabetes

Sponsor

University of Eastern Finland (Other)

Overall Status

Completed

CT.gov ID

NCT01479933

Collaborator

Academy of Finland (Other), Juho Vainio Foundation (Other), Finnish Foundation for Cardiovascular Research (Other), Diabetes Research Foundation, Finland (Other)

Enrollment

Location

Arms

Duration (Months)

9.1

Patients Per Site Per Month

Study Details

Study Description

Brief Summary

Vitamin D deficiency is widespread throughout the world, and the deficiency has been associated with several chronic diseases, such as cardiovascular diseases and diabetes. In Nordic countries, like in Finland, there is a particular variation in vitamin D status, and during wintertime, when there is no exposure to ultraviolet-B light from the sun, serum concentrations of vitamin D decrease substantially. In Finland, some 40% of middle-aged men and one third of women also have some degree of impairment of glucose metabolism.

The purpose of this trial is to investigate the effects of two different daily doses of vitamin D on glucose metabolism in men 60 years of age or older and who are vitamin D deficient, have a high body mass index and at least two characteristics of cardio-metabolic syndrome.

Altogether 102 subjects with low serum calcidiol (<60 nmol/L) will be recruited and randomized to one of the three groups: 1) 40 µg/d vitamin D3, 2) 80 µg/d vitamin D3 or 3) placebo. The supplementation period will last for 6 months from September 2011 to March 2012.

The main hypotheses of the trial are: (1.) Vitamin D supplementation will improve glucose and insulin metabolism in people with a low baseline vitamin D status, in a dose-dependent manner. (2.) Vitamin D supplementation will have an effect on the expression of genes involved in glucose and insulin metabolism and inflammation. (3.) Vitamin D supplementation will have an effect on epigenetic changes in key genes participating in vitamin D metabolism.

Condition or Disease	Intervention/Treatment	Phase
Prediabetic State Overweight Obese	Dietary Supplement: Vitamin D3 Dietary Supplement: Placebo Dietary Supplement: Vitamin D 80	N/A

Study Design

Study Type:

Interventional

Actual Enrollment :

73 participants

Allocation:

Randomized

Intervention Model:

Parallel Assignment

Masking:

Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)

Primary Purpose:

Basic Science

Official Title:

Randomized Controlled Trial of Vitamin D Supplementation on Glucose Metabolism in Subjects With Components of the Metabolic Syndrome

Study Start Date :

Sep 1, 2011

Actual Primary Completion Date :

May 1, 2012

Actual Study Completion Date :

May 1, 2012

Arms and Interventions

Arm	Intervention/Treatment
Experimental: Vitamin D 40 Vitamin D3 40 micrograms (1600 IU) per day	Dietary Supplement: Vitamin D3 Vitamin D3 40 micrograms (1600 IU) per day
Experimental: Vitamin D 80 Vitamin D3 80 micrograms (3200 IU) per day	Dietary Supplement: Vitamin D 80 Vitamin D3 80 micrograms (3200 IU) per day
Placebo Comparator: Placebo	Dietary Supplement: Placebo Inactive placebo

Arm

Intervention/Treatment

Experimental: Vitamin D 40

Vitamin D3 40 micrograms (1600 IU) per day

Dietary Supplement: Vitamin D3

Vitamin D3 40 micrograms (1600 IU) per day

Experimental: Vitamin D 80

Vitamin D3 80 micrograms (3200 IU) per day

Dietary Supplement: Vitamin D 80

Vitamin D3 80 micrograms (3200 IU) per day

Placebo Comparator: Placebo

Dietary Supplement: Placebo

Inactive placebo

Outcome Measures

Primary Outcome Measures

Insulin sensitivity [Six months]
Change in insulin sensitivity measured by oral glucose tolerance test at baseline and after 6 months

Secondary Outcome Measures

Peripheral blood mononuclear cell gene expression [Six months]
Inflammation [Baseline to six months]
Change in inflammation measured as serum cytokines and adipose tissue inflammation at baseline and after 6 months
Adipose tissue gene expression [Six months]

Eligibility Criteria

Criteria

Ages Eligible for Study:

60 Years and Older

Sexes Eligible for Study:

All

Accepts Healthy Volunteers:

Inclusion Criteria:

Age 60 years or older
Serum calcidiol <75 nmol/L
Body mass index 25-35 kg/m2
Impaired fasting glucose or impaired glucose tolerance (fasting glucose 5.6-7.0 mmol/L or 2h oral glucose tolerance test glucose 7.8-11.0 mmol/L)

Exclusion Criteria:

Any chronic disease and condition, which may hamper to follow the intervention protocol (such as alcohol abuse)
Any chronic disease or therapy which may mask or interact with the investigated effects (such as diabetes or systemic corticosteroid therapy)
Any disease or state that raises a vitamin D related safety concern (such as chronic liver, thyroid or kidney disease, hypercalcemia, sarcoidosis or other granulomatous diseases such as active chronic tuberculosis or Wegener's granulomatosis)
Use of supplements yielding vitamin D over 20 µg/d and unwillingness to discontinue the use.