Condition category
Circulatory System
Date applied
Date assigned
Last edited
Prospectively registered
Overall trial status
Recruitment status
No longer recruiting
Publication status

Plain English Summary

Background and study aims
Small studies have shown that vitamin D, a hormone that the skin usually makes using sunshine, may be able to reduce blood pressure and improve blood vessel health in some people. People who have had a stroke very often have low vitamin D levels, and people with low vitamin D tend to have higher blood pressure. People with high blood pressure have blood vessels that do not work as well as normal, and this leads to a higher risk of heart problems and strokes.
The aim of the study is therefore to test whether giving extra vitamin D to people who have had a stroke in the past helps to reduce blood pressure and improve other measures of blood vessel and heart health.

Who can participate?
Adults aged 18 years and over who have had a stroke

What does the study involve?
The study lasts for 16 weeks. Participants are randomly allocated to one of two groups, and given either a single capsule of vitamin D or a matching placebo (dummy) tablet.
Participants are assessed at the start, and 8 weeks and 16 weeks, with each visit lasting 1.5 hours.
At each visit, participants receive some or all of the following depending on which visit it is:
- Blood pressure measured
- Blood sample taken
- Test the function of the artery in their arm. The artery is scanned with an ultrasound machine before and after inflating a blood pressure cuff on their forearm for 5 minutes. The test is repeated after giving the participant a medication (GTN) spray under their tongue.
- Wear a blood pressure cuff and a heart rate monitor (ECG) for 24 hours including at home

What are the possible benefits and risks of participating?
Although participants are unlikely to benefit directly by taking part in the trial, those who receive the vitamin D might find that blood pressure is lower.
Although this dose of vitamin D has been used before and is known to be safe there is a small possibility of side effects. Participants are closely monitored for side effects caused by high calcium levels: sickness, diarrhoea, thirst or dizziness. To reduce the chance of vitamin D increasing the calcium level in their blood, participants are also asked not to take vitamin D supplements or calcium supplements whilst taking part in this study.
Having blood taken can cause some bruising. The blood pressure cuff causes mild discomfort to some people.

Where is the study run from?
Ninewells Hospital Dundee (UK)

When is the study starting and how long is it expected to run for?
September 2006 to May 2009

Who is funding the study?
Chest Heart and Stroke Scotland (UK)

Who is the main contact?
Dr Miles Witham (Scientific)

Trial website

Contact information



Primary contact

Dr Miles Witham


Contact details

Department of Medicine & Therapeutics
University of Dundee
Ninewells Hospital & Medical School
United Kingdom
+44 (0)1382 632436

Additional identifiers

EudraCT number number

Protocol/serial number


Study information

Scientific title

The effect of vitamin D replacement on markers of vascular health in stroke patients - a randomised controlled trial


Study hypothesis

That a single dose of oral vitamin D can lower blood pressure and improve endothelial function in stroke patients

Ethics approval

Tayside Local Research Ethics Committee,14/05/200, ref: 07/S1401/41

Study design

Double blind randomised placebo controlled trial.

Primary study design


Secondary study design

Randomised controlled trial

Trial setting


Trial type


Patient information sheet

Not available in web format, please use the contact details below to request a patient information sheet




A single oral dose of 100,000 U ergocalciferol (vitamin D) or placebo.

Intervention type



Not Specified

Drug names

Primary outcome measure

Blood pressure (seated office and 24 hour measurements) (added 26/02/2018: measured using a blood pressure cuff) at baseline, 8 and 16 weeks after vitamin D administration.

Secondary outcome measures

Current secondary outcome measures (as of 26/02/2018):
All outcomes are measured at baseline, and 8 and 16 weeks after vitamin D administration:
1. Endothelial function of the artery in the arm is measured using ultrasound following an inflated blood pressure cuff
2. B-type natriuretic peptide is measured from a blood sample
3. Heart rate variability is measured using a 24 hour ECG
4. Vitamin D deficiency is measured using 25OHD

Previous secondary outcome measures;
The secondary outcomes will also be measured at baseline and then at 8 and 16 weeks after vitamin D administration.

1. Endothelial function
2. B-type natriuretic peptide
3. Heart rate variability

Overall trial start date


Overall trial end date


Reason abandoned (if study stopped)


Participant inclusion criteria

1. Clinical diagnosis of completed stroke (ischaemic or haemorrhagic)
2. Serum 25-hydroxy vitamin D level less than 50 nmol/L

Participant type


Age group




Target number of participants

68 (two groups of 34)

Participant exclusion criteria

1. Hyper- or hypocalcaemia
2. Metastatic malignancy
3. Liver function tests over three times limit of normal
4. Estimated glomerular filtration rate (GFR) less than 40 ml/min
5. Previous clinical diagnosis of osteomalacia
6. Taking vitamin D preparations
7. Unable to give written informed consent
8. Unable to swallow tablets orally
9. Atrial fibrilation (to provide a more homogeneous aetiology)

Recruitment start date


Recruitment end date



Countries of recruitment

United Kingdom

Trial participating centre

Department of Medicine & Therapeutics
United Kingdom

Sponsor information


University of Dundee (UK)

Sponsor details

Research and Innovation Services
United Kingdom
+44 (0)1382 384664

Sponsor type




Funder type


Funder name

Chest Heart and Stroke Scotland (UK)

Alternative name(s)

Funding Body Type

Funding Body Subtype


Results and Publications

Publication and dissemination plan

IPD sharing statement:
The protocol is available from the authors on request but is not available online. Study data are available for non-commercial, bona-fide academic analyses in collaboration with the authors; decisions on data access will be made between the investigators and the Sponsor (University of Dundee). Participant consent for unrestricted sharing of individual participant data was not obtained
Contact for data sharing: Dr Catrina Forde (

Intention to publish date

Participant level data

Available on request

Basic results (scientific)

Publication list

1. 2010 results in

Publication citations

  1. Results

    Witham MD, Dove FJ, Sugden JA, Doney AS, Struthers AD, The effect of vitamin D replacement on markers of vascular health in stroke patients - a randomised controlled trial., Nutr Metab Cardiovasc Dis, 2012, 22, 10, 864-870, doi: 10.1016/j.numecd.2010.11.001.

Additional files

Editorial Notes

26/02/2018: The following changes were made: 1. Overall trial start date was changed from 01/06/2007 to 30/09/2006 2. Recruitment start date was changed from 01/06/2007 to 28/01/2008 3. Recruitment end date was changed from 30/11/2008 to 31/08/2008 4. Overall trial end date was changed from 30/11/2008 to 31/05/2009 5. Participant inclusion age and gender, participant level data, scientific title and basic results summary were added. 6. Primary and secondary outcome measures were updated.