Cardiovascular disease risk Circulatory System Complications and ill-defined descriptions of heart disease
Conditions
Interventions
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 t
Sponsors
University of Dundee (UK)
Eligibility
Sex/Gender
Female
Inclusion criteria
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
Exclusion criteria
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 childbearing age and not taking reliable contraception
Design outcomes
Primary
| Measure | Time frame |
|---|---|
| Macrovascular endothelial function, assessed by flow mediated dilation (FMD) according to standard guidelines at the start of the study (i.e., before the intervention) and at 4 and 8 weeks post-intervention | — |
Secondary
| Measure | Time frame |
|---|---|
| 1. Microvascular endothelial function, tested using iontophoresis according to standard guidelines 2. Arterial stiffness, measured by pulse wave velocity using the validated SphygmoCor pulse waveform analysis system 3. Office blood pressure, measured by oscillometric automatic blood pressure device 4. Metabolic and inflammatory markers: 4.1. Fasting serum lipid profiles, measured using COBAS Bio Autoanalyser 4.2. Fasting glucose, glycosylated haemoglobin (HbA1c) and insulin levels: estimates of insulin resistance calculated using the Homeostasis Model (HOMA) (fasting glucose x fasting insulin/22.5) 4.3. Adiponectin and leptin, measured 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, measured using a high sensitivity automated turbidimetric assay 4.6. Tumour necrotising factor alpha (TNF-a) and interleukin-6, measured by high sensitivity ELISA 4.7. E-selectin - an adhesion molecule expressed only on activated endothelial cells, measured by ELISA 5. Serum 25 hydroxyvitamin D and parathyroid hormone (PTH) levels All measurements taken at the start of the study (i.e., before the intervention) and at 4 and 8 weeks post-intervention | — |
Countries
United Kingdom
Outcome results
None listed