Role of Vitamin D in the Prevention and Treatment of Diseases Associated With Insulin Resistance (VIDIR)

Prospective, randomized and placebo-controlled 6-month trial of vitamin D supplementation in 130 Caucasian and vitamin D-deficient men and women aged 25 years and over. Participants will have abdominal obesity and at least one factor associated with insulin resistance. Participants will be randomized by sex, BMI and age. The primary aim is to compare the effect of daily vitamin D3 (cholecalciferol, 5000 IU) vs. placebo for 6 mo on insulin sensitivity (M-value by the gold standard method, the euglycemic hyperinsulinemic clamp). Secondary aims are to evaluate the effects of vitamin D3 vs. placebo on other indices of glucose metabolism, the lipid profile, blood pressure and anthropometric measurements. Questionnaires on physical activity and sunlight exposure, and a food frequency questionnaire will be administered at 0 and 6 mo to adjust for confounding factors. At 0 and 6 mo, changes in serum 25(OH)D will be correlated with changes in blood markers associated with insulin sensitivity [hs-CRP, inflammatory cytokines (IL-6 and TNF-alpha), adiponectin, leptin, total and undercarboxylated osteocalcin].

This research project intends to test 2 major hypotheses: (1) that vitamin D deficiency plays a causal role in the pathogenesis of insulin resistance in humans; and (2) that vitamin D increases insulin sensitivity.

Study Overview

• Status: Completed
• Conditions: Vitamin D-deficient; Insulin-resistant
• Intervention / Treatment: Other: Placebo; Dietary supplement: Vitamin D

Detailed Description

Part 1: Prospective, randomized and placebo-controlled 6-month trial of vitamin D supplementation in 130 Caucasian and vitamin D-deficient [serum 25(OH)D ≤55 nM] men and women aged 25 years and over with a BMI ≤40 kg/m2. Participants will have abdominal obesity (increased waist circumference of at least 102 cm for men and 88 cm for women) and at least one factor associated with insulin resistance, namely: (1) serum triglyceride levels of at least 1.7 mmol/L or treated dyslipidemia; (2) prediabetes or untreated type 2 diabetes (HbA1c >=5.6% or fasting glucose >=5.6 mmol/L or glucose 2h post OGTT >=7.8 mmol/L); (3) first degree relative with type 2 diabetes; (4) history of gestational diabetes. Participants will be randomized according to sex, BMI (<30 kg/m2 vs. 30 kg/m2 and over) and age (< or >=50 years old). The primary aim is to compare the effect of daily vitamin D3 (cholecalciferol, 5000 IU) vs. placebo for 6 mo on insulin sensitivity (M-value by the gold standard method, the euglycemic hyperinsulinemic clamp). Secondary aims are to evaluate the effects of vitamin D3 vs. placebo on other indices of glucose metabolism (fasting glucose, 2-h plasma glucose post OGTT, HbA1c, insulin sensitivity index (HOMA-IS using fasting glucose and insulin), insulin secretion index (HOMA-B using fasting glucose and C-peptide), insulinogenic index [(C-peptide at 30 min post OGTT - C-peptide at 0 min)/(glucose at 30 min post OGTT - glucose at 0 min)] and disposition index (insulinogenic index x M-value)), the lipid profile, blood pressure and anthropometric measurements (weight, waist and hip circumference, bioimpedance analysis). Questionnaires on physical activity and sunlight exposure, and a food frequency questionnaire will be administered at 0 and 6 mo to adjust for confounding factors. At 0 and 6 mo, biochemical markers associated with insulin sensitivity will be measured (point 2).

Part 2: Mechanistic studies comparing, before and after vitamin D3 supplementation, changes in serum 25(OH)D with changes in blood markers associated with insulin sensitivity [hs-CRP, inflammatory cytokines (IL-6 and TNF-alpha), adiponectin, leptin, total and undercarboxylated osteocalcin].

• Study Type: Interventional
• Enrollment (Actual): 96
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Canada
  • Quebec
    • Quebec city, Quebec, Canada, G1V 4G2
      • CHU de Québec, Laval University Research Center

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 25 years to 75 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• Caucasian men and women
• ≥25 yrs
• vitamin D deficiency [serum 25(OH)D concentration ≤55 nM]
• Abdominal obesity (waist circumference >=102 cm for men and >=88 cm for women) AND at least one factor associated with insulin resistance: (1) fasting serum triglycerides >=1.7 mmol/L or treated dyslipidemia; (2) prediabetes or untreated type 2 diabetes (HbA1c >=5.6% or fasting glucose >=5.6 mmol/L or 2h glucose post OGTT >=7.8 mmol/L); (3) first degree relative with type 2 diabetes; (4) history of gestational diabetes.

Exclusion Criteria:

• Type 2 diabetes under drug therapy
• HbA1c >7%
• BMI >40 kg/m2
• pregnancy or breast-feeding;
• medication influencing vitamin D or glucose metabolism in the last 3 mo
• regular consumption of supplements containing >400 IU/d of vitamin D3 over the last 2 mo;
• renal insufficiency (creatinine clearance <60 ml/min);
• cirrhosis,
• intestinal malabsorption (bypass surgery, celiac disease, etc);
• osteoporosis;
• history of nephrolithiasis;
• hypercalcemia (>2.6 mM);
• hypercalciuria (>0.6 fasting urine Ca/creatinine ratio);
• >5% change in weight in the last 3 mo;
• diseases affecting glucose metabolism (e.g. hyperthyroidism);
• pacemaker (for bioimpedance only);
• inability to provide informed consent and complete questionnaires due to physical or mental problems.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Double

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Vitamin D supplementation; 5000 IU of vitamin D3 for 6 months	Dietary supplement: Vitamin D
Placebo Comparator: Placebo; Placebo pill for 6 months	Other: Placebo

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in peripheral insulin sensitivity assessed by the euglycemic-hyperinsulinemic clamp between placebo and vitamin D groups	M-value	0 and 6 months
Change in peripheral insulin sensitivity assessed by the euglycemic-hyperinsulinemic clamp between placebo and vitamin D groups	M/I ratio	0 and 6 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in insulin sensitivity indice assessed by fasting- and oral glucose tolerance test between placebo and vitamin D groups	HOMA2%S	0 and 6 months
Change in insulin sensitivity indice assessed by fasting- and oral glucose tolerance test between placebo and vitamin D groups	Matsuda index	0 and 6 months
Change in insulin secretion indice between placebo and vitamin D groups	area under the curve for C-peptide	0 and 6 months
Change in insulin secretion indice between placebo and vitamin D groups	HOMA2-B	0 and 6 months
Change in insulin secretion indice between placebo and vitamin D groups	insulinogenic index	0 and 6 months
Change in B-cell function between placebo and vitamin D groups	Disposition index	0 and 6 months
Change in metabolic markers between placebo and vitamin D groups	HbA1c	0 and 6 months
Change in metabolic markers between placebo and vitamin D groups	Fasting glucose	0 and 6 months
Change in metabolic markers between placebo and vitamin D groups	2h glucose post-OGTT	0 and 6 months
Change in anthropometry between placebo and vitamin D groups	Weight	0 and 6 months
Change in anthropometry between placebo and vitamin D groups	BMI	0 and 6 months
Change in anthropometry between placebo and vitamin D groups	waist circumference	0 and 6 months
Change in anthropometry between placebo and vitamin D groups	hip circumference	0 and 6 months
Change in anthropometry between placebo and vitamin D groups	fat mass by bioimpedance analysis	0 and 6 months
Change in blood pressure between placebo and vitamin D groups	Systolic and diastolic blood pressure	0 and 6 months

Collaborators and Investigators

• Sponsor: CHU de Quebec-Universite Laval
• Collaborators: Canadian Diabetes Association; Laval University; Fonds de la Recherche en Santé du Québec
• Investigators: Principal Investigator: Claudia Gagnon, Dr., CHU de Quebec Research Center

Study record dates

Study Major Dates

• Study Start: January 1, 2013
• Primary Completion (Actual): June 2, 2017
• Study Completion (Actual): June 1, 2020

Study Registration Dates

• First Submitted: January 24, 2013
• First Submitted That Met QC Criteria: January 29, 2013
• First Posted (Estimate): January 30, 2013

Study Record Updates

• Last Update Posted (Actual): July 24, 2020
• Last Update Submitted That Met QC Criteria: July 22, 2020
• Last Verified: July 1, 2020

More Information

Terms related to this study

• Keywords: Insulin resistance; Vitamin D supplementation
• Additional Relevant MeSH Terms: Glucose Metabolism Disorders; Metabolic Diseases; Hyperinsulinism; Insulin Resistance; Physiological Effects of Drugs; Micronutrients; Vitamins; Bone Density Conservation Agents; Vitamin D
• Other Study ID Numbers: CDA grant no OG-3-12-3681-CG; B12-12-1095