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)
m.witham@dundee.ac.uk
Trial website
Contact information
Type
Scientific
Primary contact
Dr Miles Witham
ORCID ID
Contact details
Department of Medicine & Therapeutics
University of Dundee
Ninewells Hospital & Medical School
Dundee
DD1 9SY
United Kingdom
+44 (0)1382 632436
m.witham@dundee.ac.uk
Additional identifiers
EudraCT number
ClinicalTrials.gov number
Protocol/serial number
Res/A107
Study information
Scientific title
The effect of vitamin D replacement on markers of vascular health in stroke patients - a randomised controlled trial
Acronym
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
Interventional
Secondary study design
Randomised controlled trial
Trial setting
Hospitals
Trial type
Treatment
Patient information sheet
Not available in web format, please use the contact details below to request a patient information sheet
Condition
Stroke
Intervention
A single oral dose of 100,000 U ergocalciferol (vitamin D) or placebo.
Intervention type
Other
Phase
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
30/09/2006
Overall trial end date
31/05/2009
Reason abandoned (if study stopped)
Eligibility
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
Patient
Age group
Adult
Gender
Both
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
28/01/2008
Recruitment end date
31/08/2008
Locations
Countries of recruitment
United Kingdom
Trial participating centre
Department of Medicine & Therapeutics
Dundee
DD1 9SY
United Kingdom
Sponsor information
Organisation
University of Dundee (UK)
Sponsor details
Research and Innovation Services
Dundee
DD1 4HN
United Kingdom
+44 (0)1382 384664
j.z.houston@dundee.ac.uk
Sponsor type
University/education
Website
Funders
Funder type
Charity
Funder name
Chest Heart and Stroke Scotland (UK)
Alternative name(s)
Funding Body Type
Funding Body Subtype
Location
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 (c.forde@dundee.ac.uk)
Intention to publish date
Participant level data
Available on request
Basic results (scientific)
Publication list
1. 2010 results in http://www.ncbi.nlm.nih.gov/pubmed/21194910
Publication citations
-
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
- ISRCTN28737567_BasicResults_21Feb18.pdf Uploaded 26/02/2018