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Background: Despite growing recognition that asthma is an important cause of morbidity among American Indians, there has been no systematic study of this disease in older adults who are likely to be at high risk of complications related to asthma. Characterization of the impact of asthma among American Indian adults is necessary in order to design appropriate clinical and preventive measures., Methods: A sample of participants in the third examination of the Strong Heart Study, a multicenter, population-based, prospective study of cardiovascular disease in American Indians, completed a standardized respiratory questionnaire, performed spirometry, and underwent allergen skin testing. Participants were > or = 50 years old., Results: Of 3,197 participants in the third examination, 6.3% had physician-diagnosed asthma and 4.3% had probable asthma. Women had a higher prevalence of physician-diagnosed asthma than men (8.2% vs 3.2%). Of the 435 participants reported in the asthma substudy, morbidity related to asthma was high: among those with physician-diagnosed asthma: 97% reported trouble breathing and 52% had severe persistent disease. The mean FEV(1) in those with physician-diagnosed asthma was 61.3% of predicted, and 67.2% reported a history of emergency department visits and/or hospitalizations in the last year, yet only 3% were receiving regular inhaled corticosteroids., Conclusions: The prevalence of asthma among older American Indians residing in three separate geographic areas of the United States was similar to rates in other ethnic groups. Asthma was associated with low lung function, significant morbidity and health-care utilization, yet medications for pulmonary disease were underutilized by this population.

Objectives: To describe longitudinal changes in the prevalence of major cardiovascular disease (CVD) risk factors in aging American Indians., Design: Population-based ongoing epidemiological study., Setting: The Strong Heart Study is a study of CVD and its risk factors. Standardized examinations were repeated in 1993 to 1995 and again in 1997 to 1999., Participants: A diverse cohort of 4,549 American Indians aged 45 to 74 at the initial examinations in 1989 to 1991., Measurements: Changes in the prevalence of hypertension, low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), current smoking, and type 2 diabetes mellitus., Results: The prevalence of hypertension rose rapidly and steadily with aging. A nonsignificant decrease in LDL-C was seen in men, and men and women initially had rapid increases in the prevalence of low HDL-C. The prevalence of smoking decreased, but the prevalence of diabetes mellitus continued to rise for men and women., Conclusion: Overall, unfavorable changes in CVD risk factors were seen in the aging participants and will likely be reflected in worsening morbidity and mortality.

Background: The present article presents equations for the prediction of coronary heart disease (CHD) in a population with high rates of diabetes and albuminuria, derived from data collected in the Strong Heart Study, a longitudinal study of cardiovascular disease in 13 American Indian tribes and communities in Arizona, North and South Dakota, and Oklahoma., Methods and Results: Participants of the Strong Heart Study were examined initially in 1989-1991 and were monitored with additional examinations and mortality and morbidity surveillance. CHD outcome data through December 2001 showed that age, gender, total cholesterol, low-density lipoprotein (LDL) cholesterol, high-density lipoprotein cholesterol, smoking, diabetes, hypertension, and albuminuria were significant CHD risk factors. Hazard ratios for ages 65 to 75 years, hypertension, LDL cholesterol > or = 160 mg/dL, diabetes, and macroalbuminuria were 2.58, 2.01, 2.44, 1.66, and 2.11 in men and 2.03, 1.69, 2.17, 2.26, and 2.69 in women, compared with ages 45 to 54 years, normal blood pressure, LDL cholesterol <100 mg/dL, no diabetes, and no albuminuria. Prediction equations for CHD and a risk calculator were derived by gender with the use of Cox proportional hazards model and the significant risk factors. The equations provided good discrimination ability, as indicated by a c statistic of 0.70 for men and 0.73 for women. Results from bootstrapping methods indicated good internal validation and calibration., Conclusions: A "risk calculator" has been developed and placed on the Strong Heart Study Web site, which provides predicted risk of CHD in 10 years with input of these risk factors. This may be valuable for diverse populations with high rates of diabetes and albuminuria.

Objective: To examine the relationship between sociodemographic, clinical, and smoking history factors, and smoking cessation among older American Indians., Design: Nested cohort study of cigarette smokers in the Strong Heart Study, a longitudinal study of cardiovascular disease among American Indians., Setting: Thirteen American Indian tribes from Arizona, Oklahoma, and North and South Dakota., Participants: American Indian men and women (N = 998), aged 45-74 years, who identified themselves as smokers at the initial Strong Heart Study examination., Measurements and Main Results: Twenty-one percent of smokers quit during the 4-year follow-up period. Multivariate logistic regression was used to assess the relationship between baseline sociodemographic, clinical, and smoking history factors, and smoking cessation. Factors associated with smoking cessation included being 65-74 years old (odds ratio [OR] 2.1; 95% confidence interval [CI], 1.3 to 3.3), being examined at the Arizona regional center (OR 2.2; 95% CI 1.3, 3.7), being non-daily smokers (OR 5.4; 95% CI 1.3, 18.5), smoking fewer than 6 cigarettes daily (OR 2.8; 95% CI 1.3, 4.7), being a smoker for fewer years(OR 2.0; 95% CI 1.0, 3.9), beginning to smoke at an older age (17 years or older, OR 1.6; 95% CI 1.1, 2.4), and having a history of diabetes (OR 1.7; 95% CI 1.2, 2.3). Factors not associated with smoking cessation included gender, level of education, childhood exposure to tobacco smoking, and a history of cardiovascular diseases, cancer, or respiratory diseases., Conclusion: Several determinants of smoking cessation among older American Indians identified in this study may have important implications for designing appropriate interventions for this special population.

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.

Objective: Alterations in carotid artery structure and function may represent phenotypic measures of vascular disease that contain information beyond that which can be inferred from conventional cardiovascular disease risk assessment. However, apart from their associations with cardiovascular disease risk factors and outcome, the genetic basis of variations in carotid artery structure and function is largely unknown. The purpose of this study was to examine the genetic and environmental contributions to carotid artery structure and function in 3 large groups of American Indians., Methods and Results: Approximately 950 men and women, aged > or =18 years, in 32 extended families were examined between 1997 and 1999. By use of a variance component approach and the program Sequential Oligogenic Linkage Analysis Routines, heritabilities for carotid artery structure and function phenotypes were estimated. After accounting for the effects of covariates (sex, age, diabetes, impaired glucose tolerance, smoking, cholesterol, body surface area, and hypertension), we detected significant heritabilities (given as h2 values) for common carotid artery diastolic diameter (h2<0.44), intimal-medial wall thickness (h2<0.21), vascular mass (h2<0.27), arterial stiffness (h2<0.23), and the augmentation index (h2<0.18)., Conclusions: These results suggest that the additive effects of genes explain a moderate proportion of the variability of carotid artery structure and function.

Aortic root dilatation is a major pathophysiological mechanism for aortic regurgitation and predisposes the aortic root to dissection or rupture. However, only a small proportion of the variance of aortic root size can be explained by its known clinical and demographic correlates. The present study was undertaken to determine the heritability of echocardiographically derived aortic root diameter in the American Indian participants in the second Strong Heart Study examination. Echocardiograms were analyzed in 1373 SHS participants who had > or =1 family member in the cohort. Heritability calculations were performed by using variance component analysis as implemented in SOLAR, a computer analysis program. In a polygenic model, the variables entered and identified as covariates of larger aortic root diameter were older age, male sex, and center (P<0.001), which accounted for 35% of the overall variability of aortic root diameter. After simultaneous adjustment was made for these significant covariates, the proportion of phenotypic variance due to additive genetic contribution or residual heritability (h2) was 0.51 (SE=0.08, P<0.001). Additionally, simultaneous adjustment for height, weight, and systolic and diastolic BPs yielded slightly lower residual h2 of aortic root diameter (h2=0.44, SE=0.08, P<0.001), which accounted for 26% of the overall variance of aortic root size. Because center effects were identified as significant covariates in the analyses, h2 analyses were performed separately in Arizona, Oklahoma, and North/South Dakota centers, which confirmed that a significant proportion of the phenotypic variance of aortic root diameter is due to additive genetic contribution. Heredity explains a substantial proportion of the variability of aortic root size that is not accounted for by age, sex, body size, and blood pressure. Echocardiographic screening of family members with aortic root dilatation may identify other individuals predisposed to aortic dissection or rupture.