The INTERHEART study looked at more than 29 000 individuals in 52 countries worldwide (15 152 cases and 14 820 controls, age and sex matched). The study found that nine potentially independent risk factors such as smoking, history of hypertension and diabetes, alcohol consumption, psychosocial factors, waist/hip ratio, dietary habits, physical activity, apolipoproteins, and alcohol consumption were all related to myocardial infarction. Taken together, these nine risk factors accounted for 90% of the population attributable risk in men and 94% in women.

INTERHEART was the first major study looking at the relationship between risk factors and myocardial infarction according to age, gender, ethnic background or geographic region. Interestingly, the association between the nine risk factors and myocardial infarction were observed irrespective of gender, age or ethnic/region of the world.

Among original contributions of the INTERHEART study, the measurement of an anthropometric index of abdominal fat distribution, the waist/hip ratio, has been studied. Although the conventional measure of overall adiposity, the body mass index, has been found to be modestly associated with myocardial infarction, the risk was eliminated once the variation in abdominal obesity has been taken into account. These results emphasize the fact that we need to go beyond total obesity in the clinical evaluation of the risk associated with obesity and that rather we need to pay attention to where is located the adipose tissue. Moreover, the ratio of apolipoprotein B/apolipoprotein AI, which globally represents the proportion of atherogenic on cardioprotective particles, was found to be one the most powerful variables associated with myocardial infarction in multivariate analyses. This large case-control study has clearly demonstrated that some features of the Metabolic Syndrome such as elevated apolipoprotein B concentrations and abdominal obesity are independently associated with an increased risk of myocardial infarction.

Although results from this landmark study are very important, INTERHEART leaves us with very useful clinical lessons that could apply for everyone and everywhere in the world. It is now time to implement simple intervention strategies to change these potentially modifiable risk factors and therefore reduce the risk of myocardial infarction. Thus, an adequate examination and interpretation of these simple potentially modifiable risk factors easily obtained in clinical practice should translate a huge amount of relevant information related to heart disease.