From individual risk factors and the metabolic syndrome to global cardiometabolic risk
1 Québec Heart Institute, Hôpital Laval Research Centre, Hôpital Laval, 2725 chemin Ste-Foy Pavilion Marguerite-D’Youville, 4th Floor, Quebec City, QC G1V 4G5, Canada
2 Division of Kinesiology, Department of Social and Preventive Medicine, Université Laval, Quebec City, QC, Canada
3 Institut universitaire de cardiologie et de pneumologie, Hôpital Laval, Quebec City, QC, Canada
4 Faculty of Pharmacy, Université Laval, Quebec City, QC, Canada
5 Lipid Research Centre, CHUL Research Centre, Quebec City, QC, Canada
6 Hôpital Laval Research Centre, Hôpital Laval, Quebec City, QC G1V 4G5, Canada
* Corresponding author. Tel: +1 418 656 4863; fax: +1 418 656 4610. E-mail address: jean-pierre.despres{at}crhl.ulaval.ca
‘Traditional’ risk factors such as hypertension, elevated cholesterol, smoking, and diabetes have long been linked to cardiovascular disease (CVD). However, although remarkable progress has been made in the management of these classical CVD risk factors, obesity, the metabolic syndrome, and type 2 diabetes have reached such epidemic proportions that CVD remains a major cause of morbidity and mortality worldwide. As obesity rates soar, more and more patients are developing additional metabolic abnormalities that raise their CVD risk. Though obesity’s health hazards are well documented, physicians are sometimes perplexed by the absence of complications in some very obese patients. Equally perplexing is the fact that some moderately overweight individuals are characterized by a whole cluster of atherogenic and diabetogenic metabolic abnormalities. Because body mass index (BMI) provides little information about the location of body fat, calculating BMI as the ratio of weight over height-squared is therefore only useful as an initial step towards crudely classifying patients based on their relative weight. In this regard, numerous studies in the last two decades have confirmed that a high amount of abdominal fat, intra-abdominal (or visceral) adipose tissue in particular, is linked to a cluster of emerging metabolic risk factors/markers that may increase the risk of type 2 diabetes, CVD, and related mortality beyond excess body weight. The scientific and medical community’s recent recognition of abdominal obesity (especially the form characterized by excess visceral/ectopic fat) as the most prevalent form of the clustering atherothrombotic-inflammatory abnormalities associated with insulin resistance is an important conceptual advance with very significant clinical and public health implications. However, yet to be resolved is the extent to which the specific clustering abnormalities of visceral obesity increase overall CVD and type 2 diabetes risk estimated by traditional risk factors. There is evidence to suggest that current risk assessment algorithms may not accurately estimate the global CVD risk in patients with visceral obesity. In light of this, better methods are needed to assess the global risk of CVD and type 2 diabetes in the presence of traditional risk factors and emerging markers found in individuals with excess intra-abdominal adiposity and a ‘dysfunctional’ adipose tissue phenotype. This global risk is defined as cardiometabolic risk.
Key Words: Abdominal obesity • Cardiometabolic risk • Ectopic fat • Global CVD risk • Insulin resistance • Metabolic syndrome