The Concept of CMR

Heterogeneity of obesity

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The equivocal data on obesity and mortality may be explained by the fact that most epidemiological studies have used anthropometric correlates of total body fat (the most commonly used being body mass index; BMI: kg/m²) instead of taking into account the location of excess body fat, which seems to play a greater role in obesity-related health hazards. However, indices of overall obesity do not take into account the remarkable heterogeneity among overweight/obese patients (16). In this regard, physicians are constantly challenged by the absence of metabolic complications in some very obese patients with a relatively “normal” metabolic profile despite their obvious excess body fat. Conversely, slightly overweight patients can display a cluster of atherogenic metabolic abnormalities that increase their risk of CVD. This variation in body fat distribution among obese patients was first noted by French physician Jean Vague in the mid-forties (17). He reported that the complications generally found in obese patients depended more on the location of the excess fat rather than on obesity per se (17). Vague used the term “android obesity” to describe the high-risk form of obesity, which is characterized by an accumulation of adipose tissue in the trunk and is commonly found in men. He described the accumulation of body fat in the gluteo-femoral region—the common fat pattern of premenopausal women—as “gynoid obesity.” This type of obesity is rarely associated with the common complications of excess adiposity (18, 19). However, it took the medical community some time to realize the significance of Vague’s clinical observations about sex differences in body fat distribution. The concept of regional adipose tissue distribution only received serious consideration in the 1980s, when prospective studies also showed that abdominal fat was associated with mortality, independent of total adiposity as estimated by BMI (20-22). These studies provided sound evidence that regional fat distribution—as evaluated by anthropometric indices such as waist circumference and trunk skinfolds—was tied to increased CVD risk (20, 21, 23).

Reference

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16. Després JP, Lemieux I and Prud'homme D. Treatment of obesity: need to focus on high risk abdominally obese patients. BMJ 2001; 322: 716-20.

17. Vague J. La différenciation sexuelle: facteur déterminant des formes de l'obesité. Presse Med 1947; 339-40.

18. Terry RB, Stefanick ML, Haskell WL, et al. Contributions of regional adipose tissue depots tp plasma lipoprotein concentrations in overweight men and women: possible protective effects of thigh fat. Metabolism 1991; 40: 733-40.

19. Pouliot MC, Després JP, Nadeau A, et al. Associations between regional body fat distribution, fasting plasma free fatty acid levels and glucose tolerance in premenopausal women. Int J Obes 1990; 14: 293-302.

20. Lapidus L, Bengtsson C, Larsson BO, et al. Distribution of adipose tissue and risk of cardiovascular disease and death: a 12 year follow up of participants in the population study of women in Gothenburg, Sweaden. BMJ 1984; 289: 1261-3.

21. Larsson B, Svardsudd K, Welin L, et al. Abdominal adipose tissue distribution, obesity, and risk of cardiovascular disease and death: 13 year follow up of participants in the study of men born in 1913. BMJ (Clin Res Ed) 1984; 288: 1401-4.

22. Donahue RP, Abbott RD, Bloom E, et al. Central obesity and coronary heart disease in men. Lancet 1987; 1: 821-4.

23. Ducimetiere P, Richard J and Cambien F. The pattern of subcutaneous fat distribution in middle-aged men and the risk of coronary heart disease: the Paris Prospective Study. Int J Obes 1986; 10: 229-40.

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