Diabetes and coronary heart disease risk in Mexican Americans

Mexican Americans have a high prevalence of diabetes relative to non-Hispanic whites, but paradoxically experience a lower prevalence of myocardial infarction and lower cardiovascular mortality (at least in men). To determine whether Mexican Americans might be more resistant to the atherogenic effects of diabetes than non-Hispanic whites, we examined the associations between diabetes and myocardial infarction and selected coronary heart disease (CHD) risk factors in these two ethnic groups. The study population consisted of 5149 Mexican Americans and non-Hispanic whites who were 25 to 64 years old and recruited from the San Antonio Heart Study, a population-based study of cardiovascular risk factors and diabetes conducted between 1979 and 1988. Diabetic men were more than twice as likely to have an electrocardiography (ECG)-documented myocardial infarction than were nondiabetic men, while diabetic women were more than three times as likely to have a myocardial infarction than were nondiabetic women. In both sexes the association between myocardial infarction and diabetes was nearly identical between the two ethnic groups. In both ethnic groups diabetes was also more strongly associated with conventional CHD risk factors (e.g., triglycerides, systolic blood pressure, and high-density-lipoprotein cholesterol) in women than in men. Furthermore, these associations were at least as strong, if not stronger, in Mexican Americans as in non-Hispanic whites. Thus, these data provide no evidence to suggest that Mexican Americans are resistant to the lipid-altering effects of diabetes. We conclude that the protective effect against CHD conferred by Mexican American ethnicity may be obscured in part by the high prevalence of diabetes in this ethnic group.