The Concept of CMR

Obesity: a key modifiable risk factor for CVD

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Obesity is a chronic metabolic disorder associated with CVD and increased morbidity and mortality (6-9). Increased body fat is also associated with numerous co-morbidities such as heart disease, type 2 diabetes, stroke, hypertension, dyslipidemia, certain cancers, and sleep apnea (10). In clinical practice, however, physicians are continually challenged by the absence of metabolic abnormalities in some obese patients who have a “normal” metabolic profile despite their excess body fat. Because of this, obesity was long not considered among the “heavyweights” of modifiable CVD risk factors, such as smoking, diabetes, a dyslipidemic state, and hypertension (Figure). In addition, there is no independent association between excess body fat and CVD once the relationship between obesity and hypertension, dyslipidemia and diabetes is taken into account. The absence of an independent association between obesity and CVD could be explained by the fact that obesity is heterogeneous as a CVD risk factor.

Figure: Obesity as a modifiable cardiovascular disease (CVD) risk factor

Figure: Obesity as a modifiable cardiovascular disease (CVD) risk factor

When the high-risk form of obesity (abdominal obesity) is considered, its impact on CVD could be approximately equal to that of smoking and may even exceed that of LDL cholesterol (11). It has been suggested that any decrease in smoking-related CVD risk has been offset by the increase in obesity (12). In this regard, Mokdad et al. (13) have recently reported that, if obesity rates continue to skyrocket in the next few years, overweight and obesity caused by poor eating habits and physical inactivity will likely overtake tobacco as the leading preventable cause of mortality. In fact, they estimate that about 365,000 deaths annually are due to sedentary lifestyles and poor nutrition. Unfortunately, the sharp rise in overweight and obesity strongly suggests that this number will increase considerably in the near future. In response, the American Heart Association has reclassified obesity as a major modifiable risk factor for coronary heart disease (CHD) (14).

Reference

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12. Hu FB, Stampfer MJ, Manson JE, et al. Trends in the incidence of coronary heart disease and changes in diet and lifestyle in women. N Engl J Med 2000; 343: 530-7.

13. Mokdad AH, Marks JS, Stroup DF, et al. Actual causes of death in the United States, 2000. Jama 2004; 291: 1238-45.

14. Eckel RH and Krauss RM. American Heart Association call to action: obesity as a major risk factor for coronary heart disease. AHA Nutrition Committee. Circulation 1998; 97: 2099-100.

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