Longitudinal Course of Metabolic Health Across the Full Spectrum of Body Weight

(Présentement, le texte de cette page est disponible seulement en anglais)
Principal Investigator
Kramer, Caroline (Leadership Sinai Centre for Diabetes, Mount Sinai Hospital)

Ravi Retnakaran & Bernard Zinman

Network Affiliation
Canadian Vascular Network


1. The Health Problem/Issue

It is estimated that currently there are approximately 7 million obese adults in Canada. This is relevant for health because obesity is a major risk factor for heart disease, stroke and other vascular problems. The excess weight causes heart problems mainly because it is associated with diabetes, high blood pressure and high cholesterol or lipid levels. However, there are some individuals who are obese but do not have these metabolic alterations. In other words, despite being obese, some individuals do not present with high sugar levels, high blood pressure levels or high lipids. These individuals may have something in their body that protects them from the adverse effect of excess weight.
It is important to note that a large study demonstrated that, over the long-term, these individuals (obese without alterations in metabolic parameters) have increased risk for heart problems and death as compared to individuals with normal weight which argues against the idea that excess weight can be harmless for the body. So, there are two important questions that we need to answer: (i) what makes some people more resistant to the bad effect of increased weight? and (ii) do obese people without problems in sugar levels, blood pressure levels or lipid levels already have some alterations in their body that are just not picked up on normal check-up tests?

2. The Objectives 

The objectives of this research project are:
(i) to fully characterize people with normal weight, overweight and obesity according to the metabolic impact of their weight. In other words, we will try to discover if there is any differential characteristic (i.e. diet pattern, level of physical activity, alterations in blood pressure that are not detected in routine blood pressure measurements etc) between overweight people with alterations in sugar, blood pressure and lipids compared to those without, and
(ii) to evaluate the changes in these detailed characteristics after one year of follow up.

3. The Approach

We will evaluate people with normal weight, overweight and obesity at two visits (baseline visit and after one year of follow up). In these two visits, we will perform a series of detailed tests that are not done in routine check-ups such as tests to evaluate the blood pressure levels across 24 hours of the day, tests to evaluate the effect of insulin in the body and the secretion of insulin by the pancreas, and tests that assess the risk of having a future heart attack. These detailed tests can catch minor alterations related to excess weight that would not be evident in routine evaluations and that are important risk factors for future heart disease.

4. The Unique Factors 

This program is unique as it will evaluate the impact of excess weight on alterations in the body that are not evident on routine tests. To our knowledge, there is no previous or current study that has been specifically designed to study the impact of overweight/obesity according to their effect in the body on subtle alterations in cardiovascular risk factors. In other words, this study would be the first to evaluate in details the impact of weight on minor metabolic alteration over a period of one year.

5. How the project is relevant to the objectives of the initiative 

This program is directly related to cardiovascular research because excess weight is a major cause of heart attacks, through its effects in causing the risk factors of diabetes, hypertension and high lipid levels.

6. The Impact

A better understanding of the relationship of obesity with the presence of conditions that increase the risk of heart attacks (i.e. diabetes, hypertension and high lipid levels)is the first step to help in the prevention of heart disease in individuals with overweight/obesity. By doing a detailed characterization of individuals with excess weight, we may better understand why some people are obese and their metabolism (i.e. blood pressure, sugar levels and lipid levels) still works well while other people with the same amount of excess weight are already hypertensive and have diabetes. If we find, for example, that the people that are obese but do not have major problems already have already that are not detected on usual check-up tests, this information could help to establish preventive measures that will ultimately impact the occurrence of heart disease.