Dr Robert Petrella
801 Commissioners Rd. E
Improved lifestyle behaviour would enhance cardiac function, vascular elastic properties, and conduit vessel endothelial function with important benefits to clinical outcome measures and exercise perturbations to the cardiovascular system.
Ethics approval received from the Research Ethics Board of The University of Western Ontario on the 22nd April 2003 (review #: 09572).
Randomised prospective design.
Primary study design
Secondary study design
Randomised controlled trial
Quality of life
Patient information sheet
High-normal blood pressure and/or impaired glucose regulation.
Subjects were randomly assigned to either the SNAC intervention group or the usual care group.
The SNAC intervention group received the SNAC lifestyle intervention that combined the STEP test and exercise prescription with a version of Canadas Food Guide adapted to suit a Mediterranean-style diet. The SNAC lifestyle intervention was delivered according to Procheska and Declementes Transtheoretical Model, and delivered by each subjects family physician. To optimise familiarisation with the diet and facilitate long-term adherence, during first 8 weeks, subjects received one dinner meal per day (5 meals per week) from the laboratory as well as sample menus for breakfast and lunch. From the week 9, subjects received only sample menus for all meals.
The usual care group received "usual care" blood pressure and plasma glucose management from their family physician (for example, family physicians in this group delivered lifestyle advise to subjects as the way they normally did).
All assessments were conducted at baseline (V1), week 8 (V2), week 16 (V3), week 24 (V4), and week 52 (V5).
Primary outcome measure
Improvements in exercise capacity, left ventricular diastolic function (E/A ratio), and brachial artery endothelial function, measured at V1 - V5 (see interventions).
Secondary outcome measures
1. Caloric profile and anthropometrics, measured at V1 - V5 (see interventions)
2. Resting blood pressure and 24-hour ambulatory blood pressure, measured at V1 - V5
3. Blood chemistries (glucose, lipids, catecholamines, HbA1c, etc), measured at V1 - V5
4. Muscle sympathetic nerve activity, measured at V1 - V5
5. Geometry and elastic properties of the carotid artery, and geometry of left ventricle, measured at V1 - V5
Overall trial start date
Overall trial end date
Reason abandoned (if study stopped)
Participant inclusion criteria
1. Men and women aged 40 - 85 years who are able to provide informed consent
2. Presence of high-normal blood pressure, impaired fasting glucose, impaired glucose tolerance, or all of them
Target number of participants
Participant exclusion criteria
1. Unstable cardiovascular or metabolic disease
2. Previous diagnosis of hypertension or type 2 diabetes
3. Myocardial infarction, coronary artery bypass, or cerebrovascular ischaemia/stroke (including Transient Ischaemic Attack [TIA]) within 3 months prior to study
4. History of alcoholism, drug abuse, or other emotional, cognitive or psychiatric problems that are likely to limit compliance to the study
6. Already enrolled in a clinical research trial
Recruitment start date
Recruitment end date
Countries of recruitment
Trial participating centre
Parkwood Hospital, Room B3002
Heart and Stroke Foundation of Ontario (Canada)
Funding Body Type
Funding Body Subtype
Results and Publications
Publication and dissemination plan
Not provided at time of registration
Intention to publish date
Participant level data
Not provided at time of registration
Basic results (scientific)
1. 2011 protocol in http://www.ncbi.nlm.nih.gov/pubmed/21324150
Petrella RJ, Aizawa K, Shoemaker K, Overend T, Piche L, Marin M, Shapiro S, Atkin S, Efficacy of a family practice-based lifestyle intervention program to increase physical activity and reduce clinical and physiological markers of vascular health in patients with high normal blood pressure and/or high normal blood glucose (SNAC): study protocol for a randomized controlled trial., Trials, 2011, 12, 45, doi: 10.1186/1745-6215-12-45.