Study protocol: a randomised placebo-controlled clinical trial to study the effect of vitamin D supplementation on glycaemic control in type 2 Diabetes Mellitus SUNNY trial.

Yvonne Hm Krul-Poel,Frank Stam,Paul Lips,Hans Van Wijland,Suat Simsek,Edwin Ten Boekel

doi:10.1186/1472-6823-14-59

Yvonne Hm Krul-Poel, Frank Stam + Show 4 more

Open Access

https://doi.org/10.1186/1472-6823-14-59

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Abstract

BackgroundBesides the classical role of vitamin D on calcium and bone homeostasis, vitamin D deficiency has recently been identified as a contributing factor in the onset of insulin resistance in type 2 diabetes mellitus. However, it is uncertain whether vitamin D deficiency and poor glycaemic control are causally interrelated or that they constitute two independent features of type 2 diabetes mellitus. There are limited clinical trials carried out which measured the effect of vitamin D supplementation on glycaemic control.The objective of this study is to investigate the effect of vitamin D supplementation on glycaemic control and quality of life in patients with type 2 diabetes mellitus.Methods/designIn a randomised double-blind placebo-controlled trial conducted in five general practices in the Netherlands three hundred patients with type 2 diabetes mellitus treated with lifestyle advises or metformin or sulphonylurea-derivatives are randomised to receive either placebo or 50,000 IU Vitamin D3 at monthly intervals. The primary outcome measure is the change in glycated haemoglobin level between baseline and six months. Secondary outcome measures include blood pressure, anthropometric parameters, lipid profile, insulin resistance, quality of life, advanced glycation end products and safety profiles. Quality of life will be measured by The Short Form (SF-36) Health Survey questionnaire. Advanced glycation end products are measured by an AGE-reader.DiscussionThis trial will be the first study exploring the effect of vitamin D supplementation on both glycaemic control and quality of life in patients with type 2 diabetes mellitus. Our findings will contribute to the knowledge of the relationship between vitamin D status and insulin resistance in patients with type 2 diabetes mellitus.Trial registrationThe Netherlands trial register: NTR3154

Highlights

Besides the classical role of vitamin D on calcium and bone homeostasis, vitamin D deficiency has recently been identified as a contributing factor in the onset of insulin resistance in type 2 diabetes mellitus
This trial will be the first study exploring the effect of vitamin D supplementation on both glycaemic control and quality of life in patients with type 2 diabetes mellitus
Our findings will contribute to the knowledge of the relationship between vitamin D status and insulin resistance in patients with type 2 diabetes mellitus

Summary

Introduction

Besides the classical role of vitamin D on calcium and bone homeostasis, vitamin D deficiency has recently been identified as a contributing factor in the onset of insulin resistance in type 2 diabetes mellitus. Besides its classical role in calcium and bone homeostasis, vitamin D deficiency has recently been identified as contributing factor in the onset of insulin resistance in T2DM [5,6]. A meta-analysis done by George et al [14] demonstrated a small effect of vitamin D supplementation on fasting glucose and insulin resistance, with no effect on HbA1c Most of these reviewed studies did not include diabetic patients nor had insulin resistance as primary outcome [15,16,17,18,19,20,21,22]. Adequately powered, randomised placebo-controlled clinical trials with vitamin D supplementation are needed

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