IJCS | Volume 33, Nº1, January / February 2019

DOI: https://doi.org/10.36660/ijcs.20190210 We congratulate Pereira et al. for their study investigating the role of obesity as a risk factor for coronary artery disease (CAD) using coronary computed tomography angiography. The study included 1,383 patients, none with a history of CAD. 1 Obesity is amultifactorial chronicdisease, characterized by accumulation of subcutaneous and visceral fat, that predisposes individuals to metabolic disorders. Several mechanisms are involved in the association between obesity and atherosclerosis, including lipid abnormalities, insulin resistance, chronic inflammation, endothelial dysfunction, reduction of fibrinolysis and hypercoagulability. In addition, the production of proinflammatory cytokines, such as IL-6, TNF-alpha, MCP-1 and leptin contributes to chronic subclinical inflammation. More recent data have indicated that impaired autophagy and altered gut microbiome homeostasis are contributing factors for the development of atherosclerosis in obese individuals. 2 In the study byPereira et al., 1 the authors demonstrated, using coronary computed tomography angiography, that the prevalence of obstructive CAD was similar between obese and non-obese individuals, with a similar prevalence of cardiovascular risk factors. However, mean calcium score was significantly higher in obese than non-obese subjects. Another important finding was that, after multivariate analysis, the clinical variables age, male sex and diabetes mellitus were associated with the presence of obstructive CAD. In this study, obesity was not correlated with CAD. In a recent publication by our group, we studied a large population of obese individuals without known CAD using myocardial perfusion scintigraphy. We found that age, diabetes mellitus, typical chest pain, poor exercise capacity during stress test, need for pharmacological protocol and low left ventricular ejection fraction were associated with abnormal perfusion. In our study, we did not detect a higher percentage of perfusional abnormalities with increasing degree of obesity. 3 It is unquestionable the association between obesity, atherosclerosis, and increased total and cardiovascular mortality; however, medical research on the theme has led to controversial results. The first controversy is whether obesity is an independent risk factor for CAD or merely a risk marker, as it is associated with many pathophysiological mechanisms involved in the development of atherosclerosis. Prospective, cohort observational studies, such as the Framingham Study, the Nurses’ Health Study and the Health Professionals Follow-Up Study have demonstrated an almost linear relationship between a body mass index (BMI) ≥ 25 kg/m² and risk of CAD. Besides, the Framingham cohort study pointed towards obesity as an independent risk factor for atherosclerosis, although these findingswere not confirmed by theSevenCountries Study. 4 Another evidence for obesity as an independent risk factor for atherosclerosis emerged from the Pathobiological Determinants of Atherosclerosis in Youth (PDAY) study. In this study, the researchers, through pathological examination, analyzed coronary arteries and aorta of young people aged 15 to 30, who had accidental deaths or committed suicide.The authors found that atherosclerosis starts early in life, and that obesity is associated with higher prevalence of coronary atherosclerotic lesions, such as fatty streaks, atheroma, and complex coronary lesions, especially in men. 4 Another controversial point in the association between obesity and atherosclerosis is the “metabolically healthy obesity” phenotype, or MHO. The controversy starts with the MHO’s definition, since the diagnostic criteria varied among the studies, resulting in variations in the 55 EDITORIAL International Journal of Cardiovascular Sciences. 2020;33(1):55-56 Mailing address: Tufi Dippe Jr. Rua Rocha Pombo, 920 apto. 501. Postal Code: 80530-290, Juvevê, Curitiba, PR – Brazil. E-mail: tufidippejr@gmail.com Obesity: A Risk Marker or an Independent Risk Factor for Coronary Artery Disease? Tufi Dippe J r. a nd Rodrigo Julio Cerc i Quanta Diagnóstico por Imagem, Curitiba, PR – Brazil Obesity; Risk Factors; Atherosclerosis; Coronary Artery Disease/physiopathology; Metabolic Syndrome; Angiography, Coronary. Keywords