Trial registered on ANZCTR


Trial ID
ACTRN12607000543482
Ethics application status
Approved
Date submitted
19/10/2007
Date registered
23/10/2007
Type of registration
Prospectively registered

Titles & IDs
Public title
Long-term effects of regular consumption of tea-derived flavonoids on endothelial function, blood pressure and cardiovascular disease risk: a randomized controlled trial
Scientific title
Long-term effects of regular consumption of tea-derived flavonoids on endothelial function, blood pressure and cardiovascular disease risk: a randomized controlled trial
Universal Trial Number (UTN)
Trial acronym

Health condition
Health condition(s) or problem(s) studied:
Cardiovascular disease 2477 0
Condition category
Condition code
Cardiovascular 2578 2578 0 0
Diseases of the vasculature and circulation including the lymphatic system
Diet and nutrition 2579 2579 0 0
Other diet and nutrition disorders

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
This is a randomised double-blind, controlled, parallel-designed study. Participants will be randomly assigned to either increased flavonoid intake (~450 mg/d) from a flavonoid-rich black tea beverage, or to no increase in flavonoid intake using a tea-flavoured control beverage without flavonoids. The study will be performed over an 18 month period, with each participant being involved in a 6 month intervention.
Intervention code [1] 2207 0
Other interventions
Comparator / control treatment
Participants will be randomly assigned to either increased flavonoid intake (~450 mg/d) from a flavonoid-rich black tea beverage, or to no increase in flavonoid intake using a tea-flavoured control beverage without flavonoids.
Control group
Placebo

Outcomes
Primary outcome [1] 3485 0
Endothelial function (Brachial artery flow-mediated dilatation assessed using ultrasound measurement)
Timepoint [1] 3485 0
At baseline, 3 months and 6 months
Primary outcome [2] 3486 0
24 hour ambulatory blood pressure.
Timepoint [2] 3486 0
At baseline, 3 months and 6 months
Secondary outcome [1] 5817 0
Fasting serum total cholesterol, low density lipoprotein cholesterol, high density lipoprotein cholesterol and triglycerides using routine methods within the core clinical laroratory at Royal Perth Hospital.
Timepoint [1] 5817 0
At baseline, 3 months and 6 months
Secondary outcome [2] 5818 0
Fasting serum glucose and insulin using routine methods within the core clinical laroratory at Royal Perth Hospital
Timepoint [2] 5818 0
At baseline, 3 months and 6 months
Secondary outcome [3] 5819 0
Fasting plasma total homocysteine using an immunoassay within the core clinical laroratory at Royal Perth Hospital
Timepoint [3] 5819 0
At baseline, 3 months and 6 months
Secondary outcome [4] 5820 0
Plasma F2-isoprostanes measured using gas chromatography-mass spectrometry
Timepoint [4] 5820 0
At baseline, 3 months and 6 months
Secondary outcome [5] 5821 0
24 hour urinary nitrite and nitrate excretion
Timepoint [5] 5821 0
At baseline, 3 months and 6 months
Secondary outcome [6] 5822 0
24 hour urinary 4-O-methylgallic acid excretion
Timepoint [6] 5822 0
At baseline, 3 months and 6 months

Eligibility
Key inclusion criteria
Age at start of the study > 35 and < 75 years.
Body Mass Index (BMI) >19 and < 35 kg/m2.
4 hour day time ambulatory systolic blood pressure >120 and < 151 mmHg, and ambulatory diastolic blood pressure < 100 mmHg at screening visit.
No use of supplements 4 weeks prior to and during the study.
Haematology within the normal reference range.
Total cholesterol < 6.5 mmol/L, plasma creatinine and liver enzymes within normal reference range.
Fasting blood glucose < 6.5 mmol/L and potassium within normal reference range.
Willing to replace use of aspirin and aspirin-like painkillers (e.g. Ibuprofen) by paracetamol 4 weeks prior to and during the study.
Agreeing to be informed about medically relevant personal test-results.
Having access to a general practitioner (GP).
Informed consent signed.
Minimum age
35 Years
Maximum age
75 Years
Gender
Both males and females
Can healthy volunteers participate?
Yes
Key exclusion criteria
Being an employee or student of the University of Western Australia.
A recorded history or current diabetes or a recorded history of metabolic diseases, chronic gastrointestinal disorders, cardiovascular, malignancies, renal disease or psychiatric disorders.
Currently on a medically prescribed diet, or slimming diet or actively trying to lose weight.
Subjects with pulse <50 or >100 beats per minute.
Reported intense sporting activities > 10 hours per week.
Subjects who are taking more than three different classes of antihypertensive medications or who take anti-hypertensive medication that may effect the bioavailability of the test products and not able or willing to stop taking them.
Use of systemic antibiotics in the period of 1 month prior to the study.
Reported intolerance or allergy to test products.
Reported lactating, pregnant or wishing to become pregnant during the study.
Reported weight change ± 10% during a period of 6 months prior to the study.
Alcohol intake > 200 g alcohol/wk for women and > 300 g alcohol/wk for men.
Combined tea and coffee intake < than 2 cups per day.
Reported participation in another biomedical study 3 months before the start or during the study.
The habit of smoking cigarettes during the past year.
Reported participation in night shift work during the study period.

Study design
Purpose of the study
Treatment
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Eligible individuals will be randomly assigned 1:1 using computer generated random numbers to either the high-flavonoids tea group or the control group. Randomisation will be according to a bolck design and according to gender. Study products will be labelled with 10 different randomly generated numbers of 4 digits (5 linked to placebo and 5 linked to active). This will prevent participants from finding out what product they are consuming by talking to each other. This will also help to keep the people doing the measurements blinded. 100 envelopes, numbered 1-100, will each contain one of those 4 digit numbers (50 linking to placebo, 50 linking to active). These envelopes will be used for randomisation by opening an envelope, in consecutive order, as participants are entered into the study. These envelopes will be held by an independent person within the Univesity of Western Australia. The study coordinator will contact the independent person to obtain the next available envelope once an individual is deemed eligible. The envelope will be opened and code will be recorded.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Computer-generated random numbers using Microsoft Excel.
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?



Intervention assignment
Parallel
Other design features
Phase
Not Applicable
Type of endpoint(s)
Efficacy

Recruitment
Anticipated date of first participant enrolment
1/12/2007
Actual date of first participant enrolment
Anticipated date last participant enrolled
Actual date last participant enrolled
Anticipated date of last data collection
Actual date of last data collection
Target sample size
100
Actual sample size
Recruitment status
Recruiting
Recruitment in Australia
Recruitment state(s)

Funding & Sponsors
Funding source category [1] 2733 0
Commercial sector/Industry
Name [1] 2733 0
Unilever
Address [1] 2733 0
Unilever Research and Development
Vlaardingen B.V., Oliver van Noortlaan 120, 3133 AT Vlaardingen
Country [1] 2733 0
Netherlands
Funding source category [2] 2734 0
Government body
Name [2] 2734 0
National Health & Medical Research Council
Address [2] 2734 0
Canberra
Country [2] 2734 0
Australia
Primary sponsor type
University
Name
Univeristy of Western Australia
Address
Stirling Highway
Crawley, WA
Country
Australia
Secondary sponsor category [1] 2469 0
None
Name [1] 2469 0
Address [1] 2469 0
Country [1] 2469 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 4650 0
University of Western Australia Human Research Ethics Committee
Ethics committee address [1] 4650 0
Stirling Highway
Crawley, WA
Ethics committee country [1] 4650 0
Australia
Date submitted for ethics approval [1] 4650 0
19/09/2007
Approval date [1] 4650 0
Ethics approval number [1] 4650 0
RA/4/1/1917

Summary
Brief summary
The primary objective of this trial is to assess whether long term consumption of black tea results in increased endothelium-dependent flow-mediated dilatation of the brachial artery and a decreased 24-hour ambulatory blood pressure. Efeects on other cardiovascular disease-related measurements will also be assessed.
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 28129 0
Address 28129 0
Country 28129 0
Phone 28129 0
Fax 28129 0
Email 28129 0
Contact person for public queries
Name 11286 0
Dr Jonathan Hodgson
Address 11286 0
School of Medicine and Pharmacology
GPO Box X2213
Perth 6847
Country 11286 0
Australia
Phone 11286 0
61 (0)8 9224 0267
Fax 11286 0
61 (0)8 9224 0246
Email 11286 0
Jonathan.Hodgson@uwa.edu.au
Contact person for scientific queries
Name 2214 0
Dr Jonathan Hodgson
Address 2214 0
School of Medicine and Pharmacology
GPO Box X2213
Perth 6847
Country 2214 0
Australia
Phone 2214 0
61 (0)8 9224 0267
Fax 2214 0
61 (0)8 9224 0246
Email 2214 0
Jonathan.Hodgson@uwa.edu.au