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

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 in some people. The majority of people in Scotland have low levels of vitamin D, 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 this study is therefore to test whether giving extra vitamin D every three months to people with high blood pressure and low vitamin D levels helps to reduce blood pressure and other measures of blood vessel and heart health.

Who can participate?
Patients aged 70 and over with high blood pressure and low vitamin D levels

What does the study involve?
Participants are randomly allocated to be given either a teaspoon of vitamin D oil or a placebo (dummy) oil once every 3 months for 12 months. Participants visit the hospital at the start of the study and after 3, 6, 9 and 12 months. Each visit lasts two hours. These visits involve measuring blood pressure, taking blood samples, testing the arteries, a walking test, and answering questionnaires. After each visit, participants are given a teaspoon of the vitamin D or placebo oil to swallow. They are asked to keep a diary of any falls they have between now and the next visit.

What are the possible benefits and risks of participating?
Although participants are unlikely to benefit directly by taking part in the study, those who receive the vitamin D might find that their 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 blood calcium level, participants are asked to not take vitamin D or calcium supplements while they are 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 (UK)

When is the study starting and how long is it expected to run for?
February 2009 to January 2012

Who is funding the study?
Chief Scientist Office (UK)

Who is the main contact?
Dr Miles Witham

Trial website

Contact information



Primary contact

Dr Miles Witham


Contact details

Section of Ageing and Health
Ninewells Hospital
United Kingdom
+44 (0)1382 632436

Additional identifiers

EudraCT number number

Protocol/serial number


Study information

Scientific title

Can high-dose vitamin D supplementation reduce blood pressure and markers of cardiovascular risk in older people with isolated systolic hypertension? A randomised, double-blind, parallel group placebo controlled trial



Study hypothesis

That supplementation with 100,000 units of vitamin D3 every 3 months will produce reductions in blood pressure and improvements in markers of vascular health in patients aged greater than 70 years with isolated systolic hypertension.

Ethics approval

Fife and Forth Valley Research Ethics Committee, 15/12/2008, ref: 08/S0501/90

Study design

Randomised double-blind parallel-group 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 to request a patient information sheet


Isolated systolic hypertension


100,000 units of vitamin D3 or placebo every 3 months for 1 year.

Intervention type



Not Applicable

Drug names

Vitamin D supplementation

Primary outcome measure

Change in office blood pressure at 3 months

Secondary outcome measures

1. Change in office blood pressure at 0, 6, 9, 12 months
2. Change in 24 hour mean blood pressure at 0, 3, 6, 9, 12 months
3. Change in B-type natriuretic peptide, high sensitivity C-reactive protein (hsCRP) and homeostatic model assessment (HOMA) index at 0, 3 and 12 months
4. Change in endothelial function measured by flow-mediated dilatation of the brachial artery (FMD) at 0, 3 and 12 months
5. Change in pulse wave velocity at 0, 3 and 12 months
6. Change in 25-hydroxy vitamin D and parathyroid hormome (PTH) levels, cholesterol and triglycerides

Overall trial start date


Overall trial end date


Reason abandoned (if study stopped)


Participant inclusion criteria

1. Aged greater than or equal to 70 years, either sex
2. Office systolic blood pressure (BP) greater than 140 mmHg
3. Serum 25 hydroxy vitamin D less than 75 nmol/L

Participant type


Age group




Target number of participants


Participant exclusion criteria

1. Hypertension known to be due to a correctable underlying medical or surgical cause
2. Diastolic blood pressure greater than 90 mmHg
3. Systolic blood pressure greater than 180 mmHg
4. Estimated glomerular filtration rate less than 40 ml/min (by four-variable modification of diet in renal disease rate [MDRD] equation)
5. Liver function tests (alanine aminotransferase [ALT], bilirubin, alkaline phosphatase) greater than 3 x normal
6. Corrected calcium greater than 2.60 mmol/L or less than 2.15 mmol/L
7. Known metastatic malignancy or sarcoidosis
8. Clinical diagnosis of osteomalacia
9. History of renal calculi
10. Diagnosis of heart failure with left ventricular systolic dysfunction
11. Atrial fibrillation
12. Already taking vitamin D supplements (consumption of fish oils will not be a contraindication to enrolment)
13. Unable to give written informed consent

Recruitment start date


Recruitment end date



Countries of recruitment

United Kingdom

Trial participating centre

Ninewells Hospital
United Kingdom

Sponsor information


University of Dundee (UK)

Sponsor details

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

Sponsor type




Funder type


Funder name

Chief Scientist Office (ref: CZH/4/470)

Alternative name(s)


Funding Body Type

government organisation

Funding Body Subtype

government non-federal


United Kingdom

Results and Publications

Publication and dissemination plan

The protocol is available from the authors on request but is not available online.

IPD sharing statement
The datasets generated during and/or analysed during the current study are/will be available upon request from Dr Catrina Forde ( 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.

Intention to publish date

Participant level data

Available on request

Basic results (scientific)

See additional file ISRCTN92186858_BasicResults_01Nov17

Publication list

2013 results in:

Publication citations

  1. Results

    Witham MD, Price RJ, Struthers AD, Donnan PT, Messow CM, Ford I, McMurdo ME, Cholecalciferol treatment to reduce blood pressure in older patients with isolated systolic hypertension: the VitDISH randomized controlled trial., JAMA Intern Med, 2013, 173, 18, 1672-1679, doi: 10.1001/jamainternmed.2013.9043.

Additional files

Editorial Notes

07/11/2017: The basic results of this trial have been uploaded as an additional file. 03/11/2017: The following changes were made to the trial record: 1. The overall trial start date was changed from 01/02/2009 to 09/10/2008. 2. The overall trial end date was changed from 31/01/2012 to 31/07/2012. 01/11/2017: IPD sharing statement and plain English summary added.