Abdominal Fat and Imaging Measurements of Heart Disease

Study Overview
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Brief Summary
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Although it is frequently mentioned in the media that overweight and obesity have reached epidemic proportions worldwide and in this country, some Canadians are perplexed and sometimes confused about the role of obesity in diabetes and heart disease. In fact, the investigators even hear from time to time that there could be healthy obese individuals. In clinical practice, assessment of obesity as a risk factor for cardiovascular disease (CVD) remains a challenge as even some physicians are confused. However, studies conducted in our laboratory and by other research teams around the world over the last 20 years have clearly shown that body shape is more important than body size when evaluating the risk of overweight/obesity and that high accumulation of abdominal fat (excess belly fat) increases the risk of diabetes and cardiovascular disease (CVD). The investigators now need to better understand the link between excess belly fat and atherosclerosis (the thickening of artery walls by fatty deposits, also referred to as atherosclerotic plaque), leading to complications such as angina (chest pain) and myocardial infarction (heart attacks). Using non-invasive imaging techniques such as magnetic resonance imaging, the investigators therefore propose to examine the relationships between measures of fatness and of abdominal fat and the size of atherosclerotic plaque in large blood vessels of apparently healthy human subjects. This study is also a unique opportunity to look, for the first time, at the relationship between belly fat, blood sugar, several well-known risk factors for heart disease (cholesterol, blood pressure, cardiorespiratory fitness, etc.) and the size of atherosclerotic plaques. This research program should pave the way to the development of new improved preventive/therapeutic approaches focusing not on body weight but rather on abdominal fat and associated blood abnormalities which are predictive of the development of atherosclerotic plaques leading to the premature development of heart disease.

Official Title
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Visceral Obesity/Ectopic Fat and Non-invasive Markers of Atherosclerosis: A Cardiometabolic-cardiovascular Imaging Study

Conditions
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Visceral Obesity, Atherosclerosis, Metabolic Syndrome

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Men and women aged 35-65 years Exclusion Criteria: Massive obesity (BMI ≥ 40 kg/m2) Pharmacological treatment for lipids, hypertension and/or type 2 diabetes Clinical signs of cardiovascular disease Chronic inflammatory or auto-immune diseases Pulmonary diseases on corticosteroids Cancers not in remission History or clinical evidence of coronary heart disease (CHD) History of revascularisation procedures Current smoking Hormonal replacement therapy

Ages Eligible for Study
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Minimum Age: 35 Years
Maximum Age: 65 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Observational, longitudinal study<br>Adult men and women representative of the population of asymptomatic adult men and women aged from 35-65 years living in the Québec City metropolitan area | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in carotid vessel wall volume measured by magnetic resonance imaging (MRI) | Cross-sectional and longitudinal analyses of the relationships between indices of body fat distribution, visceral adiposity/ectopic fat deposition, cardiorespiratory fitness and non-invasive measurements of macrovascular atherosclerosis | Change between baseline and 3-year follow-up | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in epi- and pericardial fat measured by magnetic resonance imaging (MRI) |  | Change between baseline and 3-year follow-up | 
| Change in abdominal adipose tissue measured by computed tomography (CT) | Visceral and subcutaneous adipose tissue will be determined at both L2-L3 and L4-L5 levels | Change between baseline and 3-year follow-up | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Visceral obesity, Cardiometabolic risk, Atherosclerosis, Ectopic fat, Carotid plaque, Magnetic resonance imaging (MRI), Computed tomography (CT)