Plain English Summary
Background and study aims
Low levels of vitamin D have been associated with higher blood pressure and a higher risk of heart attack and stroke. These are particular problems for people with diabetes, and it is possible that giving extra vitamin D to people with diabetes who have low vitamin D levels might help to protect against heart attacks and strokes. The aim of this study is to find out whether giving vitamin D can reduce blood pressure, improve measures of blood vessel health, and improve glucose levels in diabetes.
Who can participate?
Patients aged over 18 with type 2 diabetes and low levels of vitamin D
What does the study involve?
Participants' vitamin D levels are tested and if these are low, the health of their blood vessels is assessed by doing an ultrasound scan of their arm before and after blowing up a blood pressure cuff on their arm. Blood samples are also taken to measure a series of substances that vitamin D might affect, and their blood pressure is measured. Participants are then randomly allocated take either a single large dose of vitamin D or a matching dummy (placebo) dose with no vitamin D in it. This dose acts over a period of several weeks. All participants are asked to return to repeat all of the tests 8 weeks after this single dose.
What are the possible benefits and risks of participating?
Vitamin D is a safe treatment that has been used for decades. There is a small risk of increasing calcium levels in the blood, but these levels are monitored and anyone with high levels at the start of the study is not included.
Where is the study run from?
Ninewells Hospital (UK)
When is the study starting and how long is it expected to run for?
October 2005 to June 2006
Who is funding the study?
Who is the main contact?
Dr Justine Davies
Dr Justine Davies
Dept of Clinical Pharmacology
+44 (0)1382 632180
Does Vitamin D improve markers of vascular health in type 2 diabetes? A randomised controlled trial
That Vitamin D improves endothelial function, pulse wave velocity, insulin sensitivity and markers of renin-angiotensin system activation in type 2 diabetics.
Tayside (now East of Scotland) Research Ethics committee, 13/09/2005, ref: 05/S1401/125
Randomised controlled trial
Primary study design
Secondary study design
Randomised controlled trial
Patient information sheet
Not available in web format, please use the contact details to request a patient information sheet
Type 2 diabetes mellitus
100,000 units ergocalciferol versus placebo
Intervention: 100,000 units oral Ergocalciferol (vitamin D2), given once at baseline
Comparator: Matching placebo, given once at baseline
Total duration of treatment and follow-up: 8 weeks for all treatment arms
Primary outcome measures
Current primary outcome measures as of 29/08/2017:
Flow-mediated dilatation of the brachial artery in response to reactive hyperaemia, measured by ultrasound at baseline and 8 weeks
Previous primary outcome measures:
Change in flow mediated dilatation of the brachial artery
Secondary outcome measures
Current secondary outcome measures as of 29/08/2017:
1. 25-hydroxyvitamin D, serum calcium, serum phosphate, parathyroid hormone levels, measured by blood tests at baseline and 8 weeks
2. Glycosylated haemoglobin, insulin sensitivity using HOMA index, measured by blood tests at baseline and 8 weeks
3. Office blood pressure, measured by blood pressure cuff at baseline and 8 weeks
4. Renin and angiotensin levels, measured by blood tests at baseline and 8 weeks
Previous secondary outcome measures:
Pulse wave velocity, homeostasis model assessment (HOMA) index, renin, angiotensin, Vitamin D, parathyroid hormone (PTH)
Overall trial start date
Overall trial end date
Participant inclusion criteria
1. Age ≥18 years
2. Vitamin D level <50 nmol/l
Target number of participants
Participant exclusion criteria
1. Serum creatinine >200 µmol/l
2. Liver function tests >3 x upper limit of normal
3. Corrected calcium >2.55 mmol/l or <2.15 mmol/l
4. Metastatic malignancy
5. Unable to give informed consent
Recruitment start date
Recruitment end date
Countries of recruitment
Trial participating centre
University of Dundee (UK)
11 Perth Road
+44 (0)1382 344664
Funding Body Type
private sector organisation
Funding Body Subtype
Results and Publications
Publication and dissemination plan
Not provided at time of registration
IPD sharing statement
The datasets generated during and/or analysed during the current study are available upon request from Dr Miles Witham (email@example.com). Anonymised Individual participant data on all those randomised will be made available to bona fide researchers for non-commercial use, subject to sight of an analysis plan and subject to appropriate data sharing agreements and approval from the trial sponsor.
Intention to publish date
Participant level data
Available on request
Results - basic reporting
See additional file ISRCTN46424296_BasicResults_18Aug17.pdf
2008 results in: http://www.ncbi.nlm.nih.gov/pubmed/18279409
Sugden JA, Davies JI, Witham MD, Morris AD, Struthers AD, Vitamin D improves endothelial function in patients with Type 2 diabetes mellitus and low vitamin D levels., Diabet. Med., 2008, 25, 3, 320-325, doi: 10.1111/j.1464-5491.2007.02360.x.
- ISRCTN46424296_BasicResults_18Aug17.pdf Uploaded 29/08/2017