Coronary heart disease in the Pima Indians. Electrocardiographic findings and postmortem evidence of myocardial infarction in a population with a high prevalence of diabetes mellitus.

The frequency of electrocardiographic evidence of coronary heart disease (CHD) and the rate of autopsy-proved myocardial infarction were determined in the Pima, a tribe of American Indians with a high prevalence of diabetes mellitus. The electrocardiograms of 701 Pimas, aged 40 years and over (85 per cent of the adult reservation population, 45 per cent of whom had diabetes) were read according to the Minnesota Code, and 120 postmortem examinations were reviewed for evidence of myocardial infarction. The frequency of CHD as evidenced by major Q-wave changes in the Pima (1.6/100) was about one-half that found in Tecumseh, Michigan (p less than 0.10). The relatively low rate of myocardial infarction at autopsy (15 per cent of males and 8 per cent of females aged 40 years and over) was consistent with the low prevalence of Q-wave changes. The subjects with diabetes had a higher rate of CHD than nondiabetics, both electrocardiographically and at postmortem examination, although the differences were not statistically significant. The low prevalence of CHD in the living Pima and the low rate of infarction at autopsy indicate that this tribe has a low frequency of CHD despite the extraordinarily high prevalence of diabetes mellitus.