Risk factors for acute myocardial infarction in Latin America: The INTERHEART Latin American Study
Author: F Lanas, A Avezum, et al.
Reference: Circulation 2007; 115: 1067-74,
Reviewer: Carlos Mendoza Montano, PhD, APRECOR, Guatemala, ProCOR contributing editor. E-mail:
Problem addressed: Although previous studies have described the prevalence of risk factors, knowledge of their impact on coronary heart disease in Latin America (LA) is limited. INTERHEART is an international case-control study designed to ascertain the impact of conventional and emerging cardiovascular risk factors on acute myocardial infarction (AMI) in all major regions of the world. About 15,000 cases of first AMI and a similar number of controls were enrolled from 52 countries; six countries from LA (Argentina, Brazil, Colombia, Chile, Guatemala and Mexico) participated in INTERHEART, which is the largest study of risk factors for AMI conducted in this region. This article presents the findings for LA.
Purpose of study: The specific objective was to estimate the population-attributable risk (PAR) for all risk factors and their combination in the LA region. The present report addresses in detail the strength of the associations and the absolute impact of traditional cardiovascular risk factors in the development of AMI in LA.
Location of study: Argentina, Brazil, Colombia, Chile, Guatemala and Mexico.
Study design: As part of the INTERHEART study, 1,237 cases of first acute myocardial infarction and 1888 age-, sex-, and center-matched controls were enrolled. History of smoking, hypertension, diabetes mellitus, diet, physical activity, alcohol consumption, psychosocial factors, anthropometry, and blood pressure were recorded. Non-fasting blood samples were analyzed for apolipoproteins A-1 and B-100. Logistic regression was used to estimate multivariate adjusted odds ratios (ORs) and their 95% confidence intervals (CIs).
Results: Persistent psychosocial stress (OR, 2.81; 95% CI, 2.07 to 3.82), history of hypertension (OR, 2.81; 95% CI, 2.39 to 3.31), diabetes mellitus (OR, 2.59; 95% CI, 2.09 to 3.22), current smoking (OR, 2.31; 95% CI, 1.97 to 2.71), increased waist-to-hip ratio (OR for first versus third tertile, 2.49; 95% CI, 1.97 to 3.14), and increased ratio of apolipoprotein B to A-1 (OR for first versus third tertile, 2.31; 95% CI, 1.83 to 2.94) were associated with higher risk of acute myocardial infarction. Daily consumption of fruits or vegetables (OR, 0.63; 95% CI, 0.51 to 0.78) and regular exercise (OR, 0.67; 95% CI, 0.55 to 0.82) reduced the risk of acute myocardial infarction. Abdominal obesity, abnormal lipids, and smoking were associated with high population-attributable risks of 48.5%, 40.8%, and 38.4%, respectively. Collectively, these risk factors accounted for 88% of the population-attributable risk.
Comments: According to the current study, the most important risk factors in LA are abdominal obesity, dyslipidemia, smoking and hypertension as estimated by PAR. These results are consistent with two other case-control studies conducted in Latin America (See additional references), which indicated that these four risk factors account for most of the PAR for AMI in this region. The importance of abdominal obesity as a risk factor in LA may be related to the recent rapid transition experienced in the region. Improvement in socioeconomic status in these countries has been associated with increased life expectancy, urbanization, and sedentary lifestyles causing the emergence of overweight and obesity. These changes are evidenced in the high prevalence observed in the control group of abdominal obesity, history of high blood pressure and diabetes mellitus. During recent decades, considerable evidence has accumulated on the association of psychosocial factors with CVD. An interesting finding of the present study was that individuals suffering permanent stress or several periods of stress in their lives have an increased risk of AMI.
The most important conclusion expressed by the authors of the study is that since the majority of risk of AMI in LA can be explained by modifiable risk factors such as tobacco use, abnormal lipids, abdominal obesity, and hypertension, the INTERHEART Latin America Study provides a scientific basis to develop preventive strategies in the countries of this region. For example, priority should be given to prevent overweight and obesity, particularly among children. For this purpose, programmes to promote physical activity and healthy diets should be design and implemented at school level.
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2. Ciruzzi M, Schargrodsky H, Pramparo P, Rivas Estany E, Rodriguez Naude L, de la Noval Garcia R, Gaxiola Cazarez S, Meaney E, Nass A, Finizola B, Castillo L. Attributable risks for acute myocardial infarction in four countries of Latin America. Medicina (B Aires) 2003; 63: 697-703.
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