To the Editor: The association between obesity and cardiovascular disease is controversial and was not recognized as a major independent cardiovascular risk factor by the American Heart Association until 1998. One explanation could be the high degree of comorbidity and limitations in the clinical assessment of obese patients.1 A potentially better way to define obesity is by assessing body fat, in which obesity could be defined as greater than 25% body fat in men and greater than 35% in women.2 A practical alternative could be a combined assessment of the main anthropometric measures and the degree of physical activity or fitness (ergo-anthropometric classification), which allows identification of sedentary obese (or unfit-obese) individuals, a subgroup with greater cardiovascular risk and theoretically more body fat.
Evidence supporting the superiority of ergo-anthropometric assessment1 vs isolated anthropometric assessment includes the following:
The INTERHEART study found that obesity and physical activity were 2 of the 9 factors that can explain 90% of the risk of acute myocardial infarction.3
In the Nurses' Health Study (cohort of 88,393 women), combined assessment of body weight and physical activity showed that cardiovascular risk increases progressively in active-normal weight (relative risk [RR], 1), sedentary-normal weight (RR, 1.48), active-obese (RR, 2.48), and sedentary-obese (RR, 3.44) subgroups.4
In the Women's Health Study (cohort of 38,987 women), the increased risk was as follows: active-normal weight (hazard ratio [HR], 1), sedentary-normal weight (HR, 1.08), active-overweight (HR, 1.54), active-obese (HR, 1.87), sedentary-overweight (HR, 1.88) and sedentary obese women (HR, 2.53).5
In the Framingham study, moderate and high physical activity increased life expectancy similarly in men and women.6
In a cohort of 18,892 Finnish people (8928 men), combined assessment of physical activity and obesity by any of the main indices (body mass index [BMI] calculated as weight in kilograms divided by height in meters squared, waist circumference, and waist-hip ratio) improved the predictive value of cardiovascular risk, especially in men.7
In the Lipid Research Clinics Study (2506 women and 2860 men), the combined assessment of fitness and fatness stratified cardiovascular risk in equivalent subgroups: unfit-not fat (HR: men, 1.25; women, 1.30), fit-fat (HR: men, 1.44; women, 1.32), and unfit-fat (HR: men, 1.49; women, 1.57).8
In a meta-analysis, better cardiorespiratory fitness was associated with lower risk of all-cause mortality and cardiovascular events in healthy men and women.9
These results support the validity of the new ergo-anthropometric classification,1 which includes assessment of waist circumference and physical fitness, in addition to BMI. It has the following advantages compared with the American National Heart, Lung, and Blood Institute classification: (1) the risk score it assigns is modified if lifestyle is sedentary or unfit; (2) it allows identification of sedentary-normal weight, active-overweight, active-obese, sedentary-overweight, and sedentary-obese subgroups who have an increased risk4,5; (3) it includes the waist-hip ratio in the abdominal obesity assessment because there is no consistent evidence for which of the main anthropometric measures is best10; and (4) it takes into consideration that underweight (BMI, <18.5 kg/m2) is an increased risk (especially in secondary prevention).
Recent reports on the obesity paradox (overweight-obese people with established cardiovascular disease have better prognosis compared with normal-weight patients)11 have led to doubts regarding the usefulness of anthropometric assessment and goal weight management in secondary prevention. However, unmeasured prognostic factors could be the main confounding mechanism that explains the obesity paradox.1
References
- 1.Morales Salinas A, Coca A. Obesity, physical activity and cardiovascular risk: ergo-anthropometric classification, pharmacological variables, biomarkers and “obesity paradox” [in Spanish] Med Clin (Barc) doi: 10.1016/j.medcli.2009.02.038. [published online ahead of print May 18, 2009] doi:10.1016/j.medcli.2009.04.004. [DOI] [PubMed] [Google Scholar]
- 2.Grundy SM. Obesity, metabolic syndrome, and cardiovascular disease. J Clin Endocrinol Metab. 2004;89(6):2595-2600 [DOI] [PubMed] [Google Scholar]
- 3.Yusuf S, Hawken S, Ounpuu S, et al. INTERHEART Study Investigators Effect of potentially modifiable risk factors associated with myocardial infarction in 52 countries (The INTERHEART Study): case control study. Lancet 2004;364(9438):937-952 [DOI] [PubMed] [Google Scholar]
- 4.Li TY, Rana JS, Manson JE, et al. Obesity as compared with physical activity in predicting risk of coronary heart disease in women. Circulation 2006;113(4):499-506 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 5.Weinstein AR, Sesso HD, Lee IM, et al. The joint effects of physical activity and body mass index on coronary heart disease risk in women. Arch Intern Med. 2008;168(8):884-890 [DOI] [PubMed] [Google Scholar]
- 6.Franco OH, De Laet C, Peeters A, Jonker J, Mackenbach J, Nusselder W. Effects of physical activity on life expectancy with cardiovascular disease. Arch Intern Med. 2005;165(20):2355-2360 [DOI] [PubMed] [Google Scholar]
- 7.Hu G, Tuomilehto J, Silventoinen K, Barengo N, Jousilahti P. Joint effects of physical activity, body mass index, waist circumference and waist-to-hip ratio with the risk of cardiovascular disease among middle-aged Finnish men and women. Eur Heart J. 2004;25(24):2212-2219 [DOI] [PubMed] [Google Scholar]
- 8.Stevens J, Cai J, Evenson KR, Thomas R. Fitness and fatness as predictors of mortality from all causes and from cardiovascular disease in men and women in the Lipid Research Clinics Study. Am J Epidemiol. 2002;156(9):832-841 [DOI] [PubMed] [Google Scholar]
- 9.Kodama S, Saito K, Tanaka S, et al. Cardiorespiratory fitness as a quantitative predictor of all-cause mortality and cardiovascular events in healthy men and women. JAMA 2009;301(19):2024-2035 [DOI] [PubMed] [Google Scholar]
- 10.Graham I, Atar D, Borch-Johnsen K, et al. European guidelines on cardiovascular disease prevention in clinical practice: executive summary: Fourth Joint Task Force of the European Society of Cardiology and Other Societies on Cardiovascular Disease Prevention in Clinical Practice (constituted by representatives of nine societies and by invited experts). Eur J Cardiovasc Prev Rehab. 2007;14(suppl 2):E1-E40 [DOI] [PubMed] [Google Scholar]
- 11.Lavie CJ, Milani RV, Ventura HO. Obesity and cardiovascular disease: risk factor, paradox, and impact of weight loss. J Am Coll Cardiol. 2009;53(21):1925-1932 [DOI] [PubMed] [Google Scholar]