Vitamin D AND Glucose Handling Evaluated by Glucose Clamp

Phase 2

Completed

• Conditions: Insulin Sensitivity; Intraocular Pressure

• Registration Number: NCT00809744
• Lead Sponsor: University Hospital of North Norway

Brief Summary

In this study the investigators want to compare glucose handling (insulin secretion and insulin sensitivity) in 100 persons with low and 50 persons with normal-high levels of vitamin D, using a hyperglycemic clamp technique, were sugar is given intravenously for 3 hours in order to keep the blood sugar level at 10 mmol/L. Those with low vitamin D levels will be randomized to treatment with vitamin D3 (cholecalciferol) 40 000 IU/week or placebo for 6 months before a new clamp is performed.

The study hypothesis is that persons with low vitamin D levels have impaired glucose handling which might be improved by vitamin D supplementation.

Detailed Description

Not available

Study Timeline

• Study Start: 2008-11
• Study First Submitted: 2008-12-16
• Study First Submitted QC: 2008-12-16
• Study First Posted: 2008-12-17
• Primary Completion: 2010-12
• Study Completion: 2010-12
• Status Verified: 2011-11
• Last Update Submitted: 2011-11-02
• Last Update Posted: 2011-11-03

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 160

Inclusion Criteria

• generally: Subjects are recruited from the 6th Tromsø Study
• cases: serum 25-hydroxyvitamin D-levels below the 10 percentile; low levels confirmed with new serum analyses.
• controls: serum 25-hydroxyvitamin D levels 80-95 percentile, normal-high levels confirmed with new serum analyses.

Exclusion Criteria

• diabetes
• myocardial infarction or apoplexia
• active cancer during last 5 years
• history of kidney stone
• pregnancy or premenopausal without safe anticonception
• primary hyperparathyroidism
• systolic blood pressure >175 or diastolic blood pressure >105

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Primary Outcome Measures

Name	Time	Method
intraocular pressure	6 months
insulin secretion and sensitivity as assessed by an hyperglycemic clamp	6 months

Secondary Outcome Measures

Name	Time	Method
25-hydroxyvitamin D and 1,25-dihydroxyvitamin D-levels	6 months
telomer length	6 months
serum calcium, PTH, phosphate	6 months
inflammatory markers and lipids	6 months

Trial Locations

Locations (1)

University Hospital of North Norway; 🇳🇴 Tromsø, Norway