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

Plain English Summary

Not provided at time of registration

Trial website

Contact information



Primary contact

Dr Faisel Khan


Contact details

The Institute of Cardiovascular Research (TICR)
Vascular & Inflammatory Diseases Research Unit
University of Dundee
Ninewells Hospital & Medical School
United Kingdom
+44 (0)1382 425574

Additional identifiers

EudraCT number

2008-003387-18 number

Protocol/serial number

2007cv23; 2008-003387-18; CTA: 21726/0254/001-0001

Study information

Scientific title

The effects of oral vitamin D supplementation on cardiovascular disease risk in UK South Asian women: a randomised, placebo controlled, parallel group, double blinded study


Study hypothesis

That oral supplementation of vitamin D will improve cardiovascular function and metabolic and inflammatory parameters in South Asian women.

Please note that as of 06/02/09 this record was updated to include information on the ethics approval and the trial dates. The initial anticipated start date was 01/09/2008, and the initial anticipated end date was 01/03/2009.

Ethics approval

Added 06/02/2009: Tayside Research Ethics Committee NHS gave approval on the 22nd October 2008 (ref: 08/S1402/55)

Study design

Randomised, placebo controlled, parallel group, double blinded study

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


Cardiovascular disease risk


Subjects will be given a single dose of 100,000 units of oral vitamin D3 or matching placebo. This dose will be given after baseline assessments. Ingestion will occur in the presence of the research team to ensure 100% adherence to medication.

Intervention type



Not Applicable

Drug names

Vitamin D supplementation

Primary outcome measures

Change in macrovascular endothelial function, which will be assessed by flow mediated dilation (FMD) according to standard guidelines. All measurements will be taken at the start of the study (i.e., before the intervention) and at 4 and 8 weeks post-intervention.

Secondary outcome measures

1. Microvascular endothelial function will be tested using Iontophoresis according to standard guidelines
2. Change in arterial stiffness as measured by pulse wave velocity using the validated SphygmoCor pulse waveform analysis system
3. Change in office blood pressure measured by oscillometric automatic blood pressure device
4. Change in metabolic and inflammatory markers:
4.1. Fasting serum lipid profiles: (COBAS Bio Autoanalyser)
4.2. Fasting glucose, glycosylated haemoglobin (HbA1c) and insulin levels: estimates of insulin resistance will be calculated using the Homeostasis Model (HOMA) (fasting glucose x fasting insulin/22.5)
4.3. Adiponectin and leptin using a commercially available enzyme-linked immunosorbent assay (ELISA) with good sensitivity and reproducibility
4.4. Plasminogen activator inhibitor-1 and tissue plasminogen activator antigen, both measured by ELISA
4.5. C-reactive protein will be measured using a high sensitivity automated turbidimetric assay
4.6. Tumour necrotising factor alpha (TNF-α) and interleukin-6 will be measured by high sensitivity ELISA
4.7. E-selectin - an adhesion molecule expressed only on activated endothelial cells, measured by ELISA
5. Change in serum 25 hydroxyvitamin D and parathyroid hormone (PTH) levels

All measurements will be taken at the start of the study (i.e., before the intervention) and at 4 and 8 weeks post-intervention.

Overall trial start date


Overall trial end date


Reason abandoned


Participant inclusion criteria

1. Aged greater than or equal to 18 years
2. Female
3. Serum 25 hydroxyvitamin D less than 75 nmol/L
4. South Asian ethnicity, as defined by the participant

Participant type


Age group




Target number of participants


Participant exclusion criteria

1. Symptomatic
2. Cardiovascular disease (including previous stroke, transient ischaemic attack [TIA], angina, myocardial infarction, angioplasty, coronary bypass grafting, symptomatic peripheral vascular disease, chronic heart failure, atrial fibrillation)
3. Already taking vitamin D supplements. Consumption of fish oils will not be a contraindication to enrolment as the vitamin D content is very low relative to the dose used in the study.
4. Estimated glomerular filtration rate less than 40 ml/min (by four-variable Modification of Diet in Renal Disease [MDRD] equation)
5. Liver function tests (alanine aminotransferase [ALT], bilirubin, alkaline phosphatase) greater than 3 x normal. These two criteria will ensure that sufficient renal and hepatic function is available to convert vitamin D to the active 1,25 hydroxy form.
6. Unable to give written informed consent
7. Corrected calcium level of greater than 2.60 or less than 2.15 mmol/L
8. Clinical diagnosis of osteomalacia
9. History of renal calculi, sarcoidosis or metastatic malignancy. Excluding these groups will minimise the risk of side effects from vitamin D supplementation.
10. Pregnant or of child bearing age and not taking reliable contraception

Recruitment start date


Recruitment end date



Countries of recruitment

United Kingdom

Trial participating centre

The Institute of Cardiovascular Research (TICR)
United Kingdom

Sponsor information


University of Dundee (UK)

Sponsor details

c/o Dr James Houston
Research and Innovation Services
11 Perth Road
United Kingdom
+44 (0)1382 384664

Sponsor type




Funder type


Funder name

Heart Research UK (UK)

Alternative name(s)

Funding Body Type

private sector organisation

Funding Body Subtype

other non-profit


United Kingdom

Results and Publications

Publication and dissemination plan

Not provided at time of registration

Intention to publish date

Participant level data

Not provided at time of registration

Results - basic reporting

Publication summary

2013 results in:

Publication citations

  1. Results

    Witham MD, Adams F, Kabir G, Kennedy G, Belch JJ, Khan F, Effect of short-term vitamin D supplementation on markers of vascular health in South Asian women living in the UK--a randomised controlled trial., Atherosclerosis, 2013, 230, 2, 293-299, doi: 10.1016/j.atherosclerosis.2013.08.005.

Additional files

Editorial Notes