Body weight and nonfatal myocardial infarction in a case-control study from Argentina

The relationship between overweight and obesity and the risk of acute nonfatal myocardial infarction was analyzed, using data from a case-control study from Buenos Aires, Argentina. The study included 1000 patients with acute myocardial infarction and 1000 controls, who had been admitted to the same hospitals in which the cases had been identified, for acute conditions unrelated to known or potential risk factors for coronary heart disease. Only 32% of the cases and 41% of the controls had a Quetelet's index (body mass index, BMI, kg m-2) under 25% of the cases and 51% of the controls were overweight (BMI 25 to 30), and 15% of the cases and 8% of the controls severely obese (BMI > 30). After allowance for age and sex, the relative risks (RR) were 1.4 (95% confidence interval, CI, 1.1 to 1.7) for subjects with a body mass index of 25 to 30 and 2.2 (95% CI 1.7 to 3.1) for those with a body mass index more than 30. When additional adjustment was made for hypertension, diabetes, smoking and a family history of coronary heart disease, the RR was 1.2 (95% CI 1.0 to 1.6) among subjects with a body mass index of 25 to 30 and 1.7 (95% CI 1.3 to 2.4) for those with a body mass index more than 30. The trend in risk was significant. In the stratified analysis, the RR in younger people (30-44 years) with a body mass index more than 30 was 4.7 (95% CI 2.0 to 10.8), and the association was less strong in middle and older age.