Background: Much of what is known about the occurrence of myocardial infarction (MI) in populations is derived from mortality data. International heart disease registries and recent population-based studies provide only limited incidence data from selected areas of the United States.
Methods: The Marshfield Epidemiologic Study Area (MESA), a defined geographic region where nearly all residents receive their health care from the Marshfield Clinic and affiliated hospitals, is a resource for estimating disease incidence in a general population. MI incidence rates and time trends from 1992 to 1998 were evaluated in MESA.
Results: A total of 1691 MESA residents had their first MI during the study period (age-adjusted rate, 292.4 per 100,000 per year). Rates in MESA were similar to some, and higher than other, incidence rates reported from US populations. About 20% of first MIs were detected only on death certificates. Overall incidence did not change much over time (-0.4% per year, P = 0.68), although rates declined 2.3% per year among women (P = 0.07).
Conclusions: This is the first report of MI incidence in a general population from Wisconsin. The fairly steady incidence trend and the large number of incident events detected through death certificates demonstrate the continued need for primary prevention.