Available data indicate that cardiovascular disease has become the leading cause of death in American Indians. However, limited information is available on cardiovascular disease incidence, prevalence, and risk factors in this population. Reported cardiovascular disease rates vary greatly among groups in different geographic areas. These rates have been obtained from studies of varying sizes and different methodologies. The Strong Heart Study, which uses standardized methodology, is designed to estimate cardiovascular disease mortality and morbidity rates and the prevalence of known and suspected cardiovascular disease risk factors in American Indians. The study population consists of 12 tribes in three geographic areas: an area near Phoenix, Arizona, the southwestern area of Oklahoma, and the Aberdeen area of North and South Dakota. The study includes three components. The first is a mortality survey to estimate cardiovascular disease mortality rates for 1984-1988 among tribal members aged 35-74 years, and the second is a morbidity survey to estimate incidence of both first and first or recurrent hospitalized myocardial infarction and stroke (cerebrovascular disease) among tribal members aged 45-74 years in 1984-1988, and the third is a clinical examination of 4,500 tribal members aged 45-74 years in order to estimate the prevalence of cardiovascular disease and its associations with risk factors. Family history, diet, alcohol and tobacco consumption, physical activity, degree of acculturation, and socioeconomic status are assessed in personal interviews. The physical examination includes measurements of body fat, body circumferences, and blood pressure, an examination of the heart and lungs, an evaluation of peripheral vascular disease, and a 12-lead electrocardiogram. Laboratory measurements include fasting and postload glucose, insulin, fasting lipids, apoproteins, fibrinogen, and glycated hemoglobin. Also measured are serum and urine creatinine and urinary albumin. DNA from lymphocytes is isolated and stored for future genetic studies.

Non-insulin-dependent DM has independent adverse cardiac effects, including increased LV mass and wall thicknesses, reduced LV systolic chamber and myocardial function, and increased arterial stiffness. These findings identify adverse cardiovascular effects of DM, independent of associated increases in BMI and arterial pressure, that may contribute to cardiovascular events in diabetic individuals.

Background-Although cardiovascular disease (CVD) used to be rare among American Indians, Indian Health Service data suggest that CVD mortality rates vary greatly among American Indian communities and appear to be increasing. The Strong Heart Study was initiated to investigate CVD and its risk factors in American Indians in 13 communities in Arizona, Oklahoma, and South/North Dakota. Methods and Results-A total of 4549 participants (1846 men and 2703 women 45 to 74 years old) who were seen at the baseline (1989 to 1991) examination were subjected to surveillance (average 4.2 years, 1991 to 1995), and 88% of those remaining alive underwent a second examination (1993 to 1995). The medical records of all participants were exhaustively reviewed to ascertain nonfatal cardiovascular events that occurred since the baseline examination or to definitively determine cause of death. CVD morbidity and mortality rates were higher in men than in women and were similar in the 3 geographic areas. Coronary heart disease (CHD) incidence rates among American Indian men and women were almost 2-fold higher than those in the Atherosclerosis Risk in Communities Study. Significant independent predictors of CVD in women were diabetes, age, obesity (inverse), LDL cholesterol, albuminuria, triglycerides, and hypertension. In men, diabetes, age, LDL cholesterol, albuminuria, and hypertension were independent predictors of CVD. Conclusions-At present, CHD rates in American Indians exceed rates in other US populations and may more often be fatal. Unlike other ethnic groups, American Indians appear to have an increasing incidence of CHD, possibly related to the high prevalence of diabetes. In the general US population, the rising prevalence of obesity and diabetes may reverse the decline in CVD death rates. Therefore, aggressive programs to control diabetes and its risk factors are needed.

Background-With aging, left ventricular filling tends to decrease in early diastole, reducing the mitral ratio of peak early to late diastolic filling velocity (E/A). However, the prognostic significance of low or high E/A in older adults remains to be elucidated in population-based samples. Methods and Results-Doppler echocardiograms were analyzed in 3008 American Indian participants in the second Strong Heart Study examination who had no more than mild mitral or aortic regurgitation. Participants were followed for a mean of 3 years after Doppler echocardiography to assess risks of all-cause and cardiac death associated with E/A Ͻ0.6 or Ͼ1.5; 2429 (81%) participants had normal E/A ratio, 490 (16%) had E/A Ͻ0.6, and 89 (3%) had E/A Ͼ1.5. All-cause mortality was higher with E/A Ͻ0.6 or E/A Ͼ1.5 (12% and 13% versus 6%), as was cardiac mortality (4.5% and 6.5% versus 1.6%; both PϽ0.001). Adjusting for age, sex, body mass index, systolic blood pressure, HDL and LDL cholesterol, smoking, hypertension, diabetes, coronary heart disease, left ventricular hypertrophy, and low ejection fraction (Ͻ40%), the relative risk of all-cause death with E/A Ͼ1.5 was 1.73 (95% CI, 0.99 to 3.03; Pϭ0.05); the relative risk of cardiac death was 2.8 (95% CI, 1.19 to 6.75; PϽ0.05). E/A Ͻ0.6 was not independently associated with increased all-cause or cardiac mortality (Pϭ0.19 and 0.31, respectively) after adjusting for covariates. Conclusions-In a population-based sample of middle-aged and elderly adults, mitral E/A Ͼ1.5 at baseline Doppler echocardiography is associated with 2-fold increased all-cause and 3-fold increased cardiac mortality independent of covariates; mitral E/A Ͻ0.6 was also associated with 2-fold increased all-cause and cardiac mortality but not independent of covariates.

These findings support the value of computerized measurements of QTc and QTD in noninvasive risk stratification and suggest that these surface ECG variables may reflect different underlying abnormalities of ventricular repolarization.

The aims of the Strong Heart Family Study are to clarify the genetic determinants of cardiovascular disease (CVD) risk in American Indians and to map and identify genes for CVD susceptibility. The authors describe the design of the Strong Heart Family Study (conducted between 1998 and 1999) and evaluate the heritabilities of CVD risk factors in American Indians from this study. In the first phase of the study, approximately 950 individuals, aged 18 years or more, in 32 extended families, were examined. The examination consisted of a personal interview, physical examination, laboratory tests, and an ultrasound examination of the carotid arteries. The phenotypes measured during the physical examination included anthropometry, lipoproteins, blood pressure, glycemic status, and clotting factors. Heritabilities for CVD risk factor phenotypes were estimated using a variance component approach and the program SOLAR. After accounting for the effects of covariates, the authors detected significant heritabilities for many CVD risk factor phenotypes (e.g., high density lipoprotein cholesterol (heritability = 0.50) and diastolic blood pressure (heritability = 0.34)). These results suggest that heredity explains a substantial proportion of the variability of CVD risk factors and that these heritabilities are large enough to warrant a search for major risk factor genes.

Diabetes mellitus, especially with worse glycemic control, is independently associated with abnormal LV relaxation. The severity of abnormal LV relaxation is similar to the well-known impaired relaxation associated with HTN. The combination of DM and HTN has more severe abnormal LV relaxation than groups with either condition alone. In addition, AbnREL in DM is associated with worse glycemic control.

Abstract-Diabetes has been shown to increase the risk of coronary heart disease in all populations studied. However, there is a lack of information on the relative importance of diabetes-associated risk factors for cardiovascular disease (CVD), especially the role of lipid levels, because low density lipoprotein (LDL) cholesterol often is not elevated in diabetic individuals. Key Words: low density lipoprotein cholesterol Ⅲ coronary heart disease Ⅲ diabetes mellitus Ⅲ insulin resistance Ⅲ Indians, North American M acrovascular complications are the leading causes of morbidity and mortality in diabetic patients; Ͼ60% of diabetic patients die of cardiovascular diseases. 1 In all populations studied, individuals with diabetes have a greatly increased risk of coronary heart disease (CHD) compared with nondiabetic individuals, 2 and risk of cardiovascular disease (CVD) death in diabetic individuals may be as high as that in nondiabetic individuals with previous myocardial infarction. 3 Despite this, there is insufficient information on the relative importance of CVD risk factors in persons with diabetes and strategies for risk factor reduction. Only a few population-based studies in the United States have followed individuals with diabetes. Post hoc analysis of the Multiple Risk Factor Intervention Trial (MRFIT) data set indicated that for men with diabetes, serum cholesterol level, systolic blood pressure, and cigarette smoking were significant predictors of CVD mortality. 4 The Framingham Study evaluated both men and women with diabetes and found that smoking, 5 hypertension, 5 and elevated triglycerides 6,7 were significant independent predictors of CVD. An analysis of diabetic individuals in the Rancho Bernardo cohort stressed the role of cigarette smoking in CVD deaths in older men and women