Incidence and Risk Factors for Stroke in American Indians: The Strong Heart Study

Center for American Indian Health Research, College of Public Health, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73190, USA.
Circulation (Impact Factor: 14.43). 10/2008; 118(15):1577-84. DOI: 10.1161/CIRCULATIONAHA.108.772285
Source: PubMed


There are few published data on the incidence of fatal and nonfatal stroke in American Indians. The aims of this observational study were to determine the incidence of stroke and to elucidate stroke risk factors among American Indians.
This report is based on 4549 participants aged 45 to 74 years at enrollment in the Strong Heart Study, the largest longitudinal, population-based study of cardiovascular disease and its risk factors in a diverse group of American Indians. At baseline examination in 1989 to 1992, 42 participants (age- and sex-adjusted prevalence proportion 1132/100 000, adjusted to the age and sex distribution of the US adult population in 1990) had prevalent stroke. Through December 2004, 306 (6.8%) of 4507 participants without prior stroke suffered a first stroke at a mean age of 66.5 years. The age- and sex-adjusted incidence was 679/100 000 person-years. Nonhemorrhagic cerebral infarction occurred in 86% of participants with incident strokes; 14% had hemorrhagic stroke. The overall age-adjusted 30-day case-fatality rate from first stroke was 18%, with a 1-year case-fatality rate of 32%. Age, diastolic blood pressure, fasting glucose, hemoglobin A(1c,) smoking, albuminuria, hypertension, prehypertension, and diabetes mellitus were risk factors for incident stroke.
Compared with US white and black populations, American Indians have a higher incidence of stroke. The case-fatality rate for first stroke is also higher in American Indians than in the US white or black population in the same age range. Our findings suggest that blood pressure and glucose control and smoking avoidance may be important avenues for stroke prevention in this population.

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    • "The author found that the incident rate of stroke in this cohort was 384 per 100,000 person-years for 45–54 year-olds, 727 per 100,000 person-years for 55–64 years, and 1002 per 100,000 person-years for 65–74 year-olds [40]. Compared to two cohorts (a non-Hispanic White population in Minnesota collected in 1985 and 1989, and the Framingham Heart Cohort), the Strong Heart cohort had much a higher incidence of stroke [40]. Furthermore, the 1-year mortality rate was 33.1% for women and 31% for men, compared with 24% and 21% respectively, based on pooled data from Framingham Heart Study, Atherosclerosis Risk in Communities Study and Cardiovascular Health Study. "
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    ABSTRACT: American Indians and Alaska Native (AI/AN) populations experience significant health disparities compared to non-Hispanic white populations. Cardiovascular disease and related risk factors are increasingly recognized as growing indicators of global health disparities. However, comparative reports on disparities among this constellation of diseases for AI/AN populations have not been systematically reviewed. We performed a literature review on the prevalence of diabetes, metabolic syndrome, dyslipidemia, obesity, hypertension, and cardiovascular disease; and associated morbidity and mortality among AI/AN. A total of 203 articles were reviewed, of which 31 met study criteria for inclusion. Searches were performed on PUBMED, MEDLINE, the CDC MMWR, and the Indian Health Services. Published literature that were published within the last fifteen years and provided direct comparisons between AI/AN to non-AI/AN populations were included. We abstracted data on study design, data source, AI/AN population, comparison group, and. outcome measures. A descriptive synthesis of primary findings is included. Rates of obesity, diabetes, cardiovascular disease, and metabolic syndrome are clearly higher for AI/AN populations. Hypertension and hyperlipidemia differences are more equivocal. Our analysis also revealed that there are likely regional and gender differences in the degree of disparities observed. Studies using BRFSS telephone surveys administered in English may underestimate disparities. Many AI/AN do not have telephones and/or speak English. Regional variability makes national surveys difficult to interpret. Finally, studies using self-reported data may not be accurate. Profound health disparities in cardiovascular diseases and associated risk factors for AI/AN populations persist, perhaps due to low socioeconomic status and access to quality healthcare. Successful programs will address social determinants and increase healthcare access. Community-based outreach to bring health services to the most vulnerable may also be very helpful in this effort. N/A.
    Full-text · Article · Jan 2014 · PLoS ONE
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    • "Of the initial 22,386 records, two reviewers determined independently that 42 required a review of the full manuscript. Our final primary analysis included 19 articles [7-11,18-31], with a total of 468,561 participants, derived from 18 prospective cohort studies (two articles were from the Strong Heart Study and reported the risk factors for CHD [19] and stroke [24], respectively). Eighteen of the primary papers were published in full and one was in abstract form [10]. "
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    ABSTRACT: Prospective cohort studies of prehypertension and the incidence of cardiovascular disease (CVD) are controversial after adjusting for other cardiovascular risk factors. This meta-analysis evaluated the association between prehypertension and CVD morbidity. Databases (PubMed, EMBASE and the Cochrane Library) and conference proceedings were searched for prospective cohort studies with data on prehypertension and cardiovascular morbidity. Two independent reviewers assessed the reports and extracted data. The relative risks (RRs) of CVD, coronary heart disease (CHD) and stroke morbidity were calculated and reported with 95% confidence intervals (95% CIs). Subgroup analyses were conducted on blood pressure, age, gender, ethnicity, follow-up duration, number of participants and study quality. Pooled data included the results from 468,561 participants from 18 prospective cohort studies. Prehypertension elevated the risks of CVD (RR = 1.55; 95% CI = 1.41 to 1.71); CHD (RR = 1.50; 95% CI = 1.30 to 1.74); and stroke (RR = 1.71; 95% CI = 1.55 to 1.89). In the subgroup analyses, even for low-range prehypertension, the risk of CVD was significantly higher than for optimal BP (RR = 1.46, 95% CI = 1.32 to 1.62), and further increased with high-range prehypertension (RR = 1.80, 95% CI = 1.41 to 2.31). The relative risk was significantly higher in the high-range prehypertensive populations than in the low-range populations (chi2= 5.69, P = 0.02). There were no significant differences among the other subgroup analyses (P>0.05). Prehypertension, even in the low range, elevates the risk of CVD after adjusting for multiple cardiovascular risk factors.
    Full-text · Article · Aug 2013 · BMC Medicine
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    • "The results of stepwise selected Cox proportional hazards models are reported in the Tables. For the association between HOMA-IR and incident CVD events, baseline age, sex, systolic and diastolic blood pressure, LDL cholesterol, HDL cholesterol, smoking, and micro- and macroalbuminuria were included in the initial Cox model as covariates (25,26). For the association between HOMA-IR and the development of decreased kidney function, baseline UACR, age, sex, BMI, smoking, and systolic and diastolic blood pressure were included in the initial Cox model as covariates (27,28). "
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    ABSTRACT: OBJECTIVE Prevalence of insulin resistance is high in the American Indian population, likely as a result of the high prevalence of obesity. This condition may be influential for clinical outcomes such as cardiovascular disease (CVD) and decreased kidney function.RESEARCH DESIGN AND METHODS Normal glucose tolerant (NGT) participants free of hypertension and CVD at the baseline examination (1989-1992) (N = 964) of the Strong Heart Study were selected to explore the cross-sectional association between insulin resistance quantified by homeostasis model assessment (HOMA-IR) and demographic, behavioral, and cardiometabolic variables. The longitudinal association between baseline HOMA-IR and the development of CVD was also explored. The longitudinal association between baseline HOMA-IR and the development of high urinary albumin-to-creatinine ratio was explored among nondiabetic participants (N = 1,401).RESULTSCross-sectionally, HOMA-IR was associated with sex, residence location, smoking, and high-risk cardiometabolic profile. Prospectively, insulin resistance is associated with the development of CVD and decreased kidney function in this population.CONCLUSIONS Insulin resistance may have an important role in the pathogenesis of CVD and chronic kidney disease. Since obesity contributes to the development of insulin resistance, intervention focusing on modifiable factors such as physical activity and weight control may reduce the development of these diseases.
    Full-text · Article · Jun 2013 · Diabetes care
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