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Trial registered on ANZCTR


Registration number
ACTRN12613000602729
Ethics application status
Approved
Date submitted
20/05/2013
Date registered
27/05/2013
Date last updated
21/04/2017
Type of registration
Prospectively registered

Titles & IDs
Public title
Can a Mediterranean dietary pattern improve vascular function, cognitive health and psychological wellbeing?
Scientific title
Dietary intervention for cognitive and cardiometabolic health in a healthy elderly population
Secondary ID [1] 282126 0
Nil
Universal Trial Number (UTN)
Trial acronym
MedLey
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Cognitive performance and psychological wellbeing 288623 0
Vascular function 288624 0
Cardiometabolic health 289194 0
Condition category
Condition code
Diet and Nutrition 288955 288955 0 0
Other diet and nutrition disorders
Mental Health 288958 288958 0 0
Studies of normal psychology, cognitive function and behaviour
Cardiovascular 288959 288959 0 0
Normal development and function of the cardiovascular system

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
An Australianised Mediterranean Diet (MedDiet) based on the traditional Cretan Mediterranean diet, providing 100% of energy requirements for weight maintenance for 6 months in an elderly population (age 65 years or older).

The MedDiet will consist of a high intake of vegetables, legumes, fruits, virgin olive oil, non-refined bread and cereal products and nuts; a moderate intake of low fat dairy products and lean poultry; a low intake of red meat, added sugar, salt and saturated fat, and moderate intake of red wine (if alcohol is habitually consumed) according to the NHMRC guidelines (2 drinks or less per day).

The diet will aim to provide 35-40% energy from fat with >50% coming from monounsaturated fat, 15% energy from lean protein and 40-45% energy from carbohydrate. This should achieve a ratio of monounsaturated to saturated fat of 2.

Physical activity will remain unchanged throughout the trial.

This is a 6 month study and volunteers will undergo outcome assessments at baseline and again at 3 and 6 months. Each assessment timepoint will be conducted over 2 mornings (approx. 2hrs in duration) separated by a week.
Intervention code [1] 286732 0
Prevention
Comparator / control treatment
A habitual diet, the diet normally consumed on a day-to-day basis by the control group.
Physical activity will remain unchanged throughout the trial.

This is a 6 month study and volunteers will undergo outcome assessments at baseline and again at 3 and 6 months. Each assessment timepoint will be conducted over 2 mornings (approx. 2hrs in duration) separated by a week.
Control group
Active

Outcomes
Primary outcome [1] 289084 0
Memory performance assessed by a battery of cognitive tests including: executive function: interference control (Stroop Test), strategic retrieval search (initial letter fluency and excluded letter fluency, planning (Tower of London); memory :episodic recall and recognition (Rey Auditory Verbal Learning Test (verbal learning and immediate and delayed recall and recognition), short term memory and working memory (digit span forward and digit span backwards, letter-number sequencing (verbal working memory), visual spatial memory (Benton Visual Retention Test), speed of processing and visual motor co-ordination (symbol search and coding). Assessed at 0, 3 and 6 months
Timepoint [1] 289084 0
Assessed at 0 months, 3 months, 6 months
Secondary outcome [1] 301717 0
Cognitive functioning: executive function measured using interference control (using the stroop test), strategic retrieval search (verbal fluency test), planning (Tower of London)
Timepoint [1] 301717 0
Assessed at 0 months, 3 months, 6 months
Secondary outcome [2] 301720 0
Psychological wellbeing, assessed by the Spielberger State-Trait Anxiety Inventory Form Y (STAI-7; 53), the Perceived Stress Scale (PSS; 54) and the Centre for Epidemiolgical Studies-Depression Scale (CES-D; 54) short form health survey (SF-36)
Timepoint [2] 301720 0
Assessed at 0, 3 and 6 months. SF36 assessed at 18 months (1 year since completion)
Secondary outcome [3] 301721 0
Blood pressure will be determined by automatic oscillatory using an AND Digital Blood Pressure Monitor (UA-767PC). Blood pressure will be measured at each clinic visit by staff. On each occasion 4 readings will be taken, spaced 3 minutes apart. The first reading will be discarded and the mean of the 3 readings will be recorded. Volunteers will also monitor blood pressure twice daily at home for 7 days. Blood pressure will be measured every day for 6 days, immediately after waking, and before going to bed. On each occasion 4 readings will be taken, spaced 3 minutes apart. The first reading is discarded and the mean of the next 3 readings is taken.
Timepoint [3] 301721 0
Assessed at 0 months, 3 months, 6 months, 18 months (12 months post intervention)
Secondary outcome [4] 301722 0
Body mass index, calculated as weight divided by height in metres squared. Weight will be measured using the same set of digital scales, while volunteers are wearing light clothing and no shoes. Height will be measured at time point zero only using a wall-mounted stadiometer (SECA, Hamburg, Germany) with volunteers in stockinged or bare feet.
Timepoint [4] 301722 0
Assessed at 0 months, 3 months, 6 months, 18 months (12 months after intervention was completed)
Secondary outcome [5] 301723 0
Waist and hip circumference, measured using a non-stretch tap measure, according to International Standards for Anthropometric Assessment. Waist and hip circumference
Timepoint [5] 301723 0
Assessed at 0 months, 3 months, 6 months
Secondary outcome [6] 301726 0
Plasma lipids, including low-density lipoprotein, triglycerides, high-density lipoprotein and total cholesterol
Timepoint [6] 301726 0
Assessed at 0, 3 and 6 months. Plasma lipids also assessed at 18 months (12 months since intervention was completed)
Secondary outcome [7] 301727 0
Heart rate, measured by automatic oscillometry while seated
Timepoint [7] 301727 0
Assessed at 0, 3 and 6 months and 18 months (12 months since intervention was completed)
Secondary outcome [8] 301728 0
Serum Insulin and plasma glucose
Timepoint [8] 301728 0
Assessed at 0 months, 3 months, 6 months
Secondary outcome [9] 301729 0
Plasma C-reactive protein
Timepoint [9] 301729 0
Assessed at 0 months, 3 months, 6 months
Secondary outcome [10] 301730 0
Percent body fat, measured by dual X-ray absorptiometry (DEXA)
Timepoint [10] 301730 0
Assessed at 0 months, 3 months, 6 months
Secondary outcome [11] 301731 0
Plasma F2-isoprostanes (oxidation marker)
Timepoint [11] 301731 0
Assessed at 0 months, 3 months, 6 months
Secondary outcome [12] 301732 0
Urinary metabolites, potassium:sodium, calcium:magnesium measured from 24 hour urine samples collected by participants
Timepoint [12] 301732 0
Assessed at 0 months, 3 months, 6 months
Secondary outcome [13] 301733 0
Erythrocyte fatty acids
Timepoint [13] 301733 0
Assessed at 0 months, 3 months, 6 months
Secondary outcome [14] 301734 0
Plasma carotenoids
Timepoint [14] 301734 0
Assessed at 0 months, 3 months, 6 months
Secondary outcome [15] 301735 0
Cerebral vasodilator responses (transcranial Doppler - General Electric Logiq 5 Expert) measured according to the method of Wong R et al. (2013).
Timepoint [15] 301735 0
Assessed at 0 months, 3 months, 6 months and 18 months (12 months since intervention completed)
Secondary outcome [16] 301736 0
Endothelial vasodilatory function (flow mediated dilatation), measured with a two dimensional B-mode 12 MHz tansducer (General Electric Logiq 5 Expert) in accordance with published guidelines.
Timepoint [16] 301736 0
Assessed at 0 months, 3 months, 6 months and 18 months (12 months after intervention completed)
Secondary outcome [17] 321708 0
Dietary intake using self-reported 6 day weighed food records
Timepoint [17] 321708 0
Assessed at 0, 3, 6 months and 18 months (12 months since intervention completed)
Secondary outcome [18] 321709 0
Apolipoprotein E 4
Timepoint [18] 321709 0
at baseline only
Secondary outcome [19] 321710 0
Cognitive function: executive function (Planning: Tower of London; Strategic Retrieval Search: Stroop), Memory (Rey Auditory Verbal Learning Test, Symbol search, Digit Span Backwards and coding)
Timepoint [19] 321710 0
Assessed at 18 months (1 year since completion)
Secondary outcome [20] 321711 0
Psychological wellbeing: Short form health survey (SF-36)
Timepoint [20] 321711 0
Assessed at 18 months (1 year after completed trial)

Eligibility
Key inclusion criteria
Male and females aged 65 years or more, proficient in English language, omnivorous, DemTect score 13 or over, free of dementia, non-smoker
Minimum age
65 Years
Maximum age
No limit
Gender
Both males and females
Can healthy volunteers participate?
Yes
Key exclusion criteria
Subjects who report one or more of the following: history of head/brain injury, neurological or psychiatric conditions, previous stroke, using medication for neurological or psychiatric conditions, current or recent (past 6 months) malignancy, major liver, kidney, respiratory, gastrointestinal disease, current cardiovascular disease or angina, uncontrolled hypertension (>170/100), actively undertaking a weight loss program, use of appetite suppressants or Orlistat, participation in another dietary intervention study within 30 days of commencement of the present study, smoker, or any person considered by the investigator to be unwilling, unlikely or unable to comprehend or comply with the study protocol.

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)
Eligibility will be determined by a screening questionnaire and scores from the DemTect survey (scores of 12 or less will be excluded). An independent holder of the randomisation schedule will perform treatment allocation without contact with the volunteers.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Stratified allocation by the process of minimisation based on age, gender and BMI
Masking / blinding
Open (masking not used)
Who is / are masked / blinded?



Intervention assignment
Parallel
Other design features
Phase
Not Applicable
Type of endpoint(s)
Efficacy
Statistical methods / analysis
Descriptive statistics will be provided for each treatment arm with respect to baseline characteristics. For categorical variables, counts and percentages will be provided. For continuous variables, means and SEMs will be provided (or non-parametric equivalents). Non–Normally distributed variables will be transformed appropriately before analysis. If this is not possible then non-parametric procedures will be considered. We will analyse on an intention to treat basis. A linear mixed model will be used to assess change in neurocognitive outcome after adjusting for baseline levels. In the case of any imbalance in baseline characteristics between groups, these characteristics will be included in the analysis. Statistical significance will be set at P = 0.05. Statistical analyses will be performed using SPSS for Windows (version 20.0; SPSS, Chicago, IL) and Stata (version 11, Statacorp, College Station, Texas).

A systematic review by Norman GR et al (2003) identified 38 studies which resulted in 62 effect sizes. For all but 6 studies the minimally important difference for health-related quality of life instruments was close to one half a standard deviation (mean =0.495). Based on this effect size, we calculate that 128 subjects (two groups of n=64) will provide 80% power to detect a significant (P<0.05) 0.5 SD difference in change in cognitive outcomes. A 0.5 SD improvement in cognitive outcomes is both clinically relevant and socially relevant as it would represent an annual cost saving of approximately $28 million. An additional 38 volunteers (19 per group, total n=166) will be recruited to account for a 30% subject withdrawal rate. Generally our centre has a less than 20% withdrawal rate. For flow mediated dilatation (FMD) and cerebral blood flow (TCD) we calculate that 32 participants would give 80% power to detect a statistically significant (P<0.05) 40% improvement, with an effect size of 1 in either FMD or TCD.

Recruitment
Recruitment status
Completed
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)
SA

Funding & Sponsors
Funding source category [1] 286896 0
Government body
Name [1] 286896 0
National Health and Medical Research Council
Address [1] 286896 0
Level 1
16 Marcus Clarke Street
Canberra ACT 2601
Country [1] 286896 0
Australia
Primary sponsor type
Individual
Name
Dr Karen Murphy (Chief investigator)
Address
University of South Australia
Alliance for Research in Nutrition and Activity (ARENA)
GPO Box 2471
Adelaide SA
5001
Country
Australia
Secondary sponsor category [1] 285681 0
Individual
Name [1] 285681 0
Dr Janet Bryan
Address [1] 285681 0
University of South Australia
GPO box 2471
Adelaide SA
5001
Country [1] 285681 0
Australia
Secondary sponsor category [2] 285682 0
Individual
Name [2] 285682 0
Prof Carlene Wilson
Address [2] 285682 0
Flinders University
GPO Box 2100
Adelaide, SA
5001
Country [2] 285682 0
Australia
Secondary sponsor category [3] 285683 0
Individual
Name [3] 285683 0
Prof Jonathan Hodgson
Address [3] 285683 0
University of Western Australia
35 Stirling Highway
CRAWLEY WA
6009
Australia
Country [3] 285683 0
Australia
Secondary sponsor category [4] 291890 0
Individual
Name [4] 291890 0
Prof Richard Woodman
Address [4] 291890 0
Flinders University
Country [4] 291890 0
Australia

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 288956 0
University of South Australia
Ethics committee address [1] 288956 0
Mawson Lakes Campus, Mawson Lakes Boulevard, Mawson Lakes, 5095, South Australia
Ethics committee country [1] 288956 0
Australia
Date submitted for ethics approval [1] 288956 0
Approval date [1] 288956 0
02/05/2013
Ethics approval number [1] 288956 0

Summary
Brief summary
In a 6 month dietary intervention trial, we aim to investigate the effects of an Australianised Mediterranean Diet on cognitive functioning, cardiovascular health and wellbeing in an elderly Australian free-living population. We will assess memory, executive functioning, verbal fluency and speed and accuracy, psychological well-being, weight, changes in body composition, blood lipids, blood pressure, inflammatory markers, blood glucose and insulin, and vascular endothelial function. We expect to find that an Australianised Mediterranean diet will show greater improvements in these outcomes when compared to a habitual diet.
Trial website
Trial related presentations / publications
Knight A, Davis CR, Bryan J, Hodgson J, Wilson C, Murphy KJ. A randomised controlled intervention trial evaluating the efficacy of a Mediterranean dietary pattern on cognitive function and psychological wellbeing in healthy older adults: The MedLey Study. BMC Geriatr. 2015 Apr 28;15:55. doi: 10.1186/s12877-015-0054-8.

Davis C, Bryan J, Hodgson J, Wilson C, Dillon V, Murphy KJ. A randomised controlled intervention trial evaluating the efficacy of an Australianised Mediterranean diet compared to the habitual Australian diet on cognitive function, psychological wellbeing and cardiovascular health in healthy older adults (MedLey study): protocol paper BMC Nutrition 2015, 1:35 (19 November 2015).

Public notes

Contacts
Principal investigator
Name 38498 0
Dr Karen Murphy
Address 38498 0
University of South Australia
GPO Box 2471
Adelaide, SA
5001
Country 38498 0
Australia
Phone 38498 0
+61 8 8302 1033
Fax 38498 0
+61 8 8302 2178
Email 38498 0
Karen.Murphy@unisa.edu.au
Contact person for public queries
Name 38499 0
Dr Karen Murphy
Address 38499 0
University of South Australia
Nutritional Physiology Research Centre
GPO Box 2471
Adelaide, SA
5001
Country 38499 0
Australia
Phone 38499 0
+61 8 8302 1033
Fax 38499 0
+61 8 8302 2178
Email 38499 0
Karen.Murphy@unisa.edu.au
Contact person for scientific queries
Name 38500 0
Dr Karen Murphy
Address 38500 0
University of South Australia
Nutritional Physiology Research Centre
GPO Box 2471
Adelaide, SA
5001
Country 38500 0
Australia
Phone 38500 0
+61 8 8302 1033
Fax 38500 0
+61 8 8302 2178
Email 38500 0
Karen.Murphy@unisa.edu.au

No information has been provided regarding IPD availability
Summary results
Have study results been published in a peer-reviewed journal?
Other publications
Have study results been made publicly available in another format?
Results – basic reporting
Results – plain English summary