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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 236980 0
Condition category
Condition code
Cardiovascular 4129 4129 0 0
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] 3648 0
Lifestyle
Intervention code [2] 3649 0
Treatment: Other
Intervention code [3] 3650 0
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] 5019 0
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] 5019 0
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] 5020 0
CD11b expression on monocytes is a measure of inflammation. CD11b expression is assessed via flow cytometry.
Timepoint [2] 5020 0
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.
Secondary outcome [1] 8467 0
Heart rate variability. Measured using a 5-minute 12-lead electrocardiogram (ECG).
Timepoint [1] 8467 0
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.

Eligibility
Key inclusion criteria
Treated with statins
Minimum age
18 Years
Maximum age
60 Years
Gender
Both males and females
Can healthy volunteers participate?
No
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
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] 4152 0
Self funded/Unfunded
Name [1] 4152 0
Address [1] 4152 0
Country [1] 4152 0
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] 3733 0
None
Name [1] 3733 0
Address [1] 3733 0
Country [1] 3733 0

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 29099 0
Address 29099 0
Country 29099 0
Phone 29099 0
Fax 29099 0
Email 29099 0
Contact person for public queries
Name 12256 0
Sabrina Lee
Address 12256 0
Baker IDI Heart and Diabetes Institute
PO Box 6492, St Kilda Road Central
Victoria 8008
Country 12256 0
Australia
Phone 12256 0
+61 3 85321429
Fax 12256 0
Email 12256 0
sabrina.lee@bakeridi.edu.au
Contact person for scientific queries
Name 3184 0
Michael Skilton
Address 3184 0
Baker IDI Heart and Diabetes Institute
PO Box 6492, St Kilda Road Central
Victoria 8008
Country 3184 0
Australia
Phone 3184 0
+61 3 85321539
Fax 3184 0
Email 3184 0
michael.skilton@bakeridi.edu.au

No information has been provided regarding IPD availability
Summary results
No Results