CORONARY HEART-DISEASE PREVALENCE AND ITS RELATION TO RISK-FACTORS INAMERICAN-INDIANS - THE STRONG HEART-STUDY

Although coronary heart disease (CHD) is currently the leading cause o f death among American Indians, information on the prevalence of CHD a nd its association with known cardiovascular risk factors is limited. The Strong Heart Study was initiated in 1988 to quantify cardiovascula r disease and its risk factors among three geographically diverse grou ps of American Indians. Members of 13 Indian communities in Arizona, O klahoma, and South and North Dakota between 45 and 74 years of age und erwent a physical examination that included medical history; an electr ocardiogram; anthropometric and blood pressure measurements; an oral g lucose tolerance test; and measurements of fasting plasma lipoproteins , fibrinogen, insulin, hemoglobin A1(c), and urinary albumin. Prevalen ce rates of definite myocardial infarction and definite CHD were highe r in men than in women at all three centers (p < 0.0001) and higher in those with diabetes mellitus (p = 0.002 in men and p = 0.0003 in wome n). Diabetes was associated with relatively higher prevalence rates of myocardial infarction (diabetic: nondiabetic prevalence ratio = 3.8 v s. 1.9) and CHD (prevalence ratio = 4.6 vs. 1.8) in women than in men. Prevalence rates of heart disease were lowest in the communities in A rizona; prevalence rates were similar in Oklahoma and South Dakota/Nor th Dakota and were two- to threefold higher than those in Arizona. By logistic regression, prevalent CHD among American Indians was signific antly and independently related to age, diabetes, hypertension, albumi nuria, percentage of body fat, smoking, high concentrations of plasma insulin, and low concentrations of high density lipoprotein cholestero l. In contrast to reports from other non-Indian populations, diabetes was the strongest risk factor. The lower prevalence of CHD among India ns in Arizona is distinctive in view of their higher rates of diabetes , obesity, hypertension, and albuminuria, but it may be partly related to their low frequency of smoking and their low concentrations of tot al and low density lipoprotein cholesterol. These findings from the in itial Strong Heart Study examination emphasize the importance of diabe tes and its associated variables as risk factors for CHD in Native Ame rican populations.