- BACKGROUND: Although declines in mortality rates have occurred in most developed countries, increases are being seen in developing countries. Our knowledge of risk factors for acute myocardial infarction (AMI) is largely derived from studies in the former. Applicability of these results to other populations is unknown. The objectives of INTER-HEART are to determine the association between risk factors and AMI within populations defined by ethnicity and/or geographic region and to assess the relative importance of risk factors across these populations. METHODS: INTER-HEART is a study of 14,000 cases of AMI and 16,000 matched control patients from 46 countries, which was conducted with a standardized protocol. Questionnaires were translated into 11 languages; physical measurements were obtained, and 20 mL of blood was drawn and shipped frozen to a central laboratory in Canada. The study will evaluate the importance of conventional and emerging risk factors within each geographic region and whether their impact varies by region. RESULTS: INTER-HEART is sponsored by the World Health Organization and the World Heart Federation and has received funding from several peer-reviewed agencies and many different pharmaceutical companies. A vanguard phase (February 1999 to 2000) enrolled 4000 subjects from 41 countries. Full data collection started in April 2000 and is expected to be completed by October 2002. CONCLUSIONS: Several years of targeted work have allowed the development of the concepts that were tested in the pilot studies. This has ensured the feasibility of INTER-HEART. This study has the potential to have a major impact in developing a worldwide strategy for cardiovascular disease prevention, especially in developing countries and nonwhite populations.