ANZCTR - Registration

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Trial registered on ANZCTR

Registration number

ACTRN12609000464268

Ethics application status

Approved

Date submitted

13/11/2008

Date registered

16/06/2009

Date last updated

6/07/2012

Type of registration

Retrospectively registered

Titles & IDs

Public title

Influence of dietary omega-6/omega-3 fatty acid ratio on vascular health in patients treated with statins

Scientific title

Randomised crossover trial of high and low dietary omega-6/omega-3 fatty acid ratios on arterial compliance, and CD11b expression in patients treated with statins

Universal Trial Number (UTN)

Trial acronym

Linked study record

Health condition

Health condition(s) or problem(s) studied:

Cardiovascular disease

Condition category

Condition code

Cardiovascular

Coronary heart disease

Intervention/exposure

Study type

Interventional

Description of intervention(s) / exposure

a) Consumption of a diet with a low omega-6/omega-3 fatty acid ratio.
b) The diet is given for 4 weeks. Observations/measures are made on day 0 and day 28.
c) Dietary intake, consumed as 5 meals per day plus snacks, every day for a 4-week period; dietary ratio of omega-6/omega-3 fatty acids is 1.7:1.
d) Oral (diet)
2. There is an 8-week washout period between the dietary interventions.

Intervention code [1]

Lifestyle

Intervention code [2]

Treatment: Other

Intervention code [3]

Prevention

Comparator / control treatment

a) Consumption of a diet with a high omega-6/omega-3 fatty acid ratio.
b) The diet is given for 4 weeks. Observations/measures are made on day 0 and day 28.
c) Dietary intake, consumed as 5 meals per day plus snacks, every day for a 4-week period; dietary ratio of omega-6/omega-3 fatty acids is 30:1.
d) Oral (diet)

Control group

Dose comparison

Outcomes

Primary outcome [1]

Vascular stiffness (compliance & distensibility).
Assessment of brachial artery elasticity (compliance & distensibility) using high-resolution ultrasound.
Assessment of systemic compliance/stiffness using pulse wave analysis derived from applanation tonometry.

Timepoint [1]

All measures are assessed on day 0 and day 28 (after 4 weeks dietary intervention). The trial has a randomised crossover design, with an 8-week washout phase. The measures are repeated for the second diet.

Primary outcome [2]

CD11b expression on monocytes is a measure of inflammation. CD11b expression is assessed via flow cytometry.

Timepoint [2]

Secondary outcome [1]

Heart rate variability. Measured using a 5-minute 12-lead electrocardiogram (ECG).

Timepoint [1]

Eligibility

Key inclusion criteria

Treated with statins

Minimum age

18 Years

Maximum age

60 Years

Sex

Both males and females

Can healthy volunteers participate?

Key exclusion criteria

Prior history of clinically relevant atheroma, current smokers, diabetes, obesity.

Study design

Purpose of the study

Prevention

Allocation to intervention

Randomised controlled trial

Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)

Methods used to generate the sequence in which subjects will be randomised (sequence generation)

Masking / blinding

Who is / are masked / blinded?

Intervention assignment

Other design features

Phase

Not Applicable

Type of endpoint/s

Statistical methods / analysis

Recruitment

Recruitment status

Recruiting

Date of first participant enrolment

Anticipated

21/11/2007

Actual

Date of last participant enrolment

Anticipated

Actual

Date of last data collection

Anticipated

Actual

Sample size

Target

Accrual to date

Final

Recruitment in Australia

Recruitment state(s)

Funding & Sponsors

Funding source category [1]

Self funded/Unfunded

Name [1]

Address [1]

Country [1]

Primary sponsor type

Other Collaborative groups

Name

Baker IDI Heart & Diabetes Institute

Address

PO Box 6492
St Kilda Road Central
VIC 8008

Country

Australia

Secondary sponsor category [1]

None

Name [1]

Address [1]

Country [1]

Ethics approval

Ethics application status

Approved

Summary

Brief summary

Patients with high blood lipid levels are currently treated with dietary modification and lifestyle treatment with the addition of statins in cases where lipid levels remain elevated. Statins are the best lipid-lowering pharmaceuticals currently available; however patients treated with statins remain at high risk of cardiac events despite a marked reduction in low-density lipoprotein (LDL) cholesterol, and modest effects on triglycerides and high-density lipoprotein (HDL) cholesterol. In contrast, fish oils increase HDL-cholesterol and markedly reduce triglycerides, with little effect on LDL-cholesterol. They may therefore be ideal for combination therapy with statins to improve vascular health and reduce cardiovascular mortality.  
Omega-3 polyunsaturated fatty acids (PUFA) are the active ingredient in fish oil. Previous studies have demonstrated that fish oils can have beneficial effects on the vasculature and decrease the risk of coronary heart disease. The cardiac and vascular benefits of dietary omega-3 PUFA could be due to their effects on lipids, blood pressure, thrombosis, endothelial function and/or anti-arrhythmic & anti-inflammatory effects. Omega-6 PUFA are known to compete with omega-3 PUFA for many common metabolic enzymes and during incorporation into lipid fractions and membranes. This has highlighted the potential importance of the dietary ratio of omega-6 to omega-3 PUFA. This ratio may be of more importance than assessing dietary omega-3 PUFA alone. The average dietary omega-6/omega-3 ratio is between 10:1 and 17:1 in Western countries, and as high as 30:1 in certain populations. It has been estimated that the optimal dietary ratio of omega-6/omega-3 PUFA is ~1.7:1. Despite this, there is little evidence regarding the effects of the omega-6/omega-3 PUFA ratio on measures of cardiovascular health. It is important to establish whether decreasing the ratio of dietary omega-6 to omega-3 fatty acids can further improve the cardiovascular profile of patients on statins. 

Hypothesis
That altering the dietary ratio of omega-6/omega-3 polyunsaturated fatty acids will influence vascular health – consistent with a low omega-6/omega-3 polyunsaturated fatty acid ratio diet being cardio-protective.

Trial website

Trial related presentations / publications

Public notes

Contacts

Principal investigator

Name

Address

Country

Phone

Fax

Contact person for public queries

Name

Sabrina Lee

Address

Baker IDI Heart and Diabetes Institute
PO Box 6492, St Kilda Road Central
Victoria 8008

Country

Australia

Phone

+61 3 85321429

Fax

sabrina.lee@bakeridi.edu.au

Contact person for scientific queries

Name

Michael Skilton

Address

Baker IDI Heart and Diabetes Institute
PO Box 6492, St Kilda Road Central
Victoria 8008

Country

Australia

Phone

+61 3 85321539

Fax

michael.skilton@bakeridi.edu.au

No information has been provided regarding IPD availability

What supporting documents are/will be available?

No Supporting Document Provided

Results publications and other study-related documents

Documents added manually

No documents have been uploaded by study researchers.

Documents added automatically

No additional documents have been identified.

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