Incidence and risk factors for stroke in American Indians: the Strong Heart Study

Health Care Disparities in Stroke Rehabilitation

Stroke outcomes are influenced by factors such as education, lifestyle, and access to care, which determine the extent of functional recovery. Disparities in stroke rehabilitation research have traditionally included age, race/ethnicity, and sex, but other areas make up a gap in the literature. This article conducted a literature review of original research articles published between 2008 and 2022. The article also expands on research that highlights stroke disparities in risk factors, rehabilitative stroke care, language barriers, outcomes for stroke survivors, and interventions focused on rehabilitative stroke disparities.

Psychometric Properties of Controlled Oral Word Association (COWA) Test and Associations With Education and Bilingualism in American Indian Adults: The Strong Heart Study

The Controlled Oral Word Association (COWA) test is used to assess phonemic fluency and executive function. Formal validation of test scores is important for accurate cognitive evaluation. However, there is a dearth of psychometric validation among American Indian adults. Given high burden of dementia risk and key contextual factors associated with cognitive assessments, this represents a critical oversight. In a large, longitudinal population-based cohort study of adult American Indians, we examined several validity inferences for COWA, including scoring, generalization, and extrapolation inferences, by investigation of factor structure, internal consistency, test-retest reliability, and differential test functioning. We found adequate unidimensional model fit, with high factor loadings. Internal consistency reliability and test-retest reliability were 0.88 and 0.77, respectively, for the full group. COWA scores were lowest among the oldest, lowest education, bilingual speakers; group effects for sex and bilingual status were small; age effect was medium; and education effect was largest. However, Wide Range Achievement Test (WRAT) score effect was stronger than education effect, suggesting better contextualization may be needed. These results support interpretation of total COWA score, including across sex, age, or language use strata.

Dyslipidemia in American Indian Adolescents and Young Adults: Strong Heart Family Study

BACKGROUND

Although many studies on the association between dyslipidemia and cardiovascular disease (CVD) exist in older adults, data on the association among adolescents and young adults living with disproportionate burden of cardiometabolic disorders are scarce.

METHODS AND RESULTS

The SHFS (Strong Heart Family Study) is a multicenter, family-based, prospective cohort study of CVD in an American Indian populations, including 12 communities in central Arizona, southwestern Oklahoma, and the Dakotas. We evaluated SHFS participants, who were 15 to 39 years old at the baseline examination in 2001 to 2003 (n=1440). Lipids were measured after a 12-hour fast. We used carotid ultrasounds to detect plaque at baseline and follow-up in 2006 to 2009 (median follow-up=5.5 years). We identified incident CVD events through 2020 with a median follow-up of 18.5 years. We used shared frailty proportional hazards models to assess the association between dyslipidemia and subclinical or clinical CVD, while controlling for covariates. Baseline dyslipidemia prevalence was 55.2%, 73.6%, and 78.0% for participants 15 to 19, 20 to 29, and 30 to 39 years old, respectively. Approximately 2.8% had low-density lipoprotein cholesterol ≥160 mg/dL, which is higher than the recommended threshold for lifestyle or medical interventions in young adults of 20 to 39 years old. During follow-up, 9.9% had incident plaque (109/1104 plaque-free participants with baseline and follow-up ultrasounds), 11.0% had plaque progression (128/1165 with both baseline and follow-up ultrasounds), and 9% had incident CVD (127/1416 CVD-free participants at baseline). Plaque incidence and progression were higher in participants with total cholesterol ≥200 mg/dL, low-density lipoprotein cholesterol ≥160 mg/dL, or non-high-density lipoprotein cholesterol ≥130 mg/dL, while controlling for covariates. CVD risk was independently associated with low-density lipoprotein cholesterol ≥160 mg/dL.

CONCLUSIONS

Dyslipidemia is a modifiable risk factor that is associated with both subclinical and clinical CVD, even among the younger American Indian population who have unexpectedly high rates of significant CVD events. Therefore, this population is likely to benefit from a variety of evidence-based interventions including screening, educational, lifestyle, and guideline-directed medical therapy at an early age.

Incidence of Stroke in Indigenous Populations of Countries With a Very High Human Development Index: A Systematic Review

BACKGROUND AND OBJECTIVES

Cardiovascular disease contributes significantly to disease burden among many Indigenous populations. However, data on stroke incidence in Indigenous populations are sparse. We aimed to investigate what is known of stroke incidence in Indigenous populations of countries with a very high Human Development Index (HDI), locating the research in the broader context of Indigenous health.

METHODS

We identified population-based stroke incidence studies published between 1990 and 2022 among Indigenous adult populations of developed countries using PubMed, Embase, and Global Health databases, without language restriction. We excluded non-peer-reviewed sources, studies with fewer than 10 Indigenous people, or not covering a 35- to 64-year minimum age range. Two reviewers independently screened titles, abstracts, and full-text articles and extracted data. We assessed quality using "gold standard" criteria for population-based stroke incidence studies, the Newcastle-Ottawa Scale for risk of bias, and CONSIDER criteria for reporting of Indigenous health research. An Indigenous Advisory Board provided oversight for the study.

RESULTS

From 13,041 publications screened, 24 studies (19 full-text articles, 5 abstracts) from 7 countries met the inclusion criteria. Age-standardized stroke incidence rate ratios were greater in Aboriginal and Torres Strait Islander Australians (1.7-3.2), American Indians (1.2), Sámi of Sweden/Norway (1.08-2.14), and Singaporean Malay (1.7-1.9), compared with respective non-Indigenous populations. Studies had substantial heterogeneity in design and risk of bias. Attack rates, male-female rate ratios, and time trends are reported where available. Few investigators reported Indigenous stakeholder involvement, with few studies meeting any of the CONSIDER criteria for research among Indigenous populations.

DISCUSSION

In countries with a very high HDI, there are notable, albeit varying, disparities in stroke incidence between Indigenous and non-Indigenous populations, although there are gaps in data availability and quality. A greater understanding of stroke incidence is imperative for informing effective societal responses to socioeconomic and health disparities in these populations. Future studies into stroke incidence in Indigenous populations should be designed and conducted with Indigenous oversight and governance to facilitate improved outcomes and capacity building.

REGISTRATION INFORMATION

PROSPERO registration: CRD42021242367.

Cardiovascular Disease Burden and Outcomes Among American Indian and Alaska Native Medicare Beneficiaries

Importance

American Indian and Alaska Native persons face significant health disparities; however, data regarding the burden of cardiovascular disease in the current era is limited.

Objective

To determine the incidence and prevalence of cardiovascular disease, the burden of comorbid conditions, including cardiovascular disease risk factors, and associated mortality among American Indian and Alaska Native patients with Medicare insurance.

Design, Setting, and Participants

This was a population-based cohort study conducted from January 2015 to December 2019 using Medicare administrative data. Participants included American Indian and Alaska Native Medicare beneficiaries 65 years and older enrolled in both Medicare part A and B fee-for-service Medicare. Statistical analyses were performed from November 2022 to April 2023.

Main Outcomes and Measures

The annual incidence, prevalence, and mortality associated with coronary artery disease (CAD), heart failure (HF), atrial fibrillation/flutter (AF), and cerebrovascular disease (stroke or transient ischemic attack [TIA]).

Results

Among 220 598 American Indian and Alaska Native Medicare beneficiaries, the median (IQR) age was 72.5 (68.5-79.0) years, 127 402 were female (57.8%), 78 438 (38.8%) came from communities in the most economically distressed quintile in the Distressed Communities Index. In the cohort, 44.8% of patients (98 833) were diagnosed with diabetes, 61.3% (135 124) were diagnosed with hyperlipidemia, and 72.2% (159 365) were diagnosed with hypertension during the study period. The prevalence of CAD was 38.6% (61 125 patients) in 2015 and 36.7% (68 130 patients) in 2019 (P < .001). The incidence of acute myocardial infarction increased from 6.9 per 1000 person-years in 2015 to 7.7 per 1000 patient-years in 2019 (percentage change, 4.79%; P < .001). The prevalence of HF was 22.9% (36 288 patients) in 2015 and 21.4% (39 857 patients) in 2019 (P < .001). The incidence of HF increased from 26.1 per 1000 person-years in 2015 to 27.0 per 1000 person-years in 2019 (percentage change, 4.08%; P < .001). AF had a stable prevalence of 9% during the study period (2015: 9.4% [14 899 patients] vs 2019: 9.3% [25 175 patients]). The incidence of stroke or TIA decreased slightly throughout the study period (12.7 per 1000 person-years in 2015 and 12.1 per 1000 person-years in 2019; percentage change, 5.08; P = .004). Fifty percent of patients (110 244) had at least 1 severe cardiovascular condition (CAD, HF, AF, or cerebrovascular disease), and the overall mortality rate for the cohort was 19.8% (43 589 patients).

Conclusions and Relevance

In this large cohort study of American Indian and Alaska Native patients with Medicare insurance in the US, results suggest a significant burden of cardiovascular disease and cardiometabolic risk factors. These results highlight the critical need for future efforts to prioritize the cardiovascular health of this population.

American Indians and atrial fibrillation

The American Indian population is known to experience high rates of cardiovascular disease and have a heightened vulnerability to severe outcomes driven by an overall poor health status and lower access to quality health care. Our group has previously published an analysis demonstrating that American Indians have the highest risk of atrial fibrillation (AF), as well as of AF-related stroke, when compared with other races and ethnicities. Despite this, AF in this population has not been extensively studied and additional publications are scarce. Our review article provides an up-to-date summary of the relevant literature addressing the relationship between race, ethnicity, and AF by focusing on American Indians.

Psychological and social support associations with mortality and cardiovascular disease in middle-aged American Indians: the Strong Heart Study

PURPOSE

Our study examined psychosocial risk and protective features affecting cardiovascular and mortality disparities in American Indians, including stress, anger, cynicism, trauma, depression, quality of life, and social support.

METHODS

The Strong Heart Family Study cohort recruited American Indian adults from 12 communities over 3 regions in 2001-2003 (N = 2786). Psychosocial measures included Cohen Perceived Stress, Spielberger Anger Expression, Cook-Medley cynicism subscale, symptoms of post-traumatic stress disorder, Centers for Epidemiologic Studies Depression scale, Short Form 12-a quality of life scale, and the Social Support and Social Undermining scale. Cardiovascular events and all-cause mortality were evaluated by surveillance and physician adjudication through 2017.

RESULTS

Participants were middle-aged, 40% male, with mean 12 years formal education. Depression symptoms were correlated with anger, cynicism, poor quality of life, isolation, criticism; better social support was correlated with lower cynicism, anger, and trauma. Adjusted time-to-event regressions found that depression, (poor) quality of life, and social isolation scores formed higher risk for mortality and cardiovascular events, and social support was associated with lower risk. Social support partially explained risk associations in causal mediation analyses.

CONCLUSION

Altogether, our findings suggest that social support is associated with better mood and quality of life; and lower cynicism, stress, and disease risk-even when said risk may be increased by comorbidities. Future research should examine whether enhancing social support can prospectively reduce risk, as an efficient, cost-effective intervention opportunity that may be enacted at the community level.

Vascular Risk Factor Prevalence and Trends in Native Americans with Ischemic Stroke

INTRODUCTION

Native Americans have a higher incidence and prevalence of stroke and the highest stroke-related mortality among race-ethnic groups in the United States. We aimed to analyze trends in the ischemic stroke (IS) vascular risk factor prevalence in Native Americans along with a comparison to the other race-ethnic groups.

METHODS

National Inpatient Sample (NIS) database was used to explore the prevalence of risk factors among hospitalized IS patients during 2000 - 2016. Prevalence estimates were calculated for each risk factor within each race-ethnic group in 6 time periods. Linear trends were explored using linear regression models, with differences in trends between the Native American group and the other race-ethnic groups assessed using interaction terms. The analysis accounted for the complex sampling design, including hospital clusters, NIS stratum, and trend weights for analyzing multiple years of NIS data.

RESULTS

Native Americans constituted 5472 of the 1,278,784 IS patients. The age-and-sex-standardized prevalence of hypertension (slope = 2.24, p < 0.001), hyperlipidemia (slope = 6.29, p < 0.001), diabetes (slope = 2.04, p = 0.005), atrial fibrillation/flutter (trend slope = 0.80, p = 0.011), heart failure (trend slope = 0.73, p = 0.036) smoking (trend slope= 3.65, p < 0.001), and alcohol (slope = 0.60, p = 0.019) increased among Native Americans. They showed larger increases in hypertension prevalence compared to Blacks, Hispanics, and Asian/Pacific Islanders and in smoking prevalence compared to Hispanics and Asian/Pacific Islanders. By the year 2015-2016, Native Americans had the highest overall prevalence of diabetes, coronary artery disease, smoking, and alcohol among all race-ethnic groups.

CONCLUSION

The prevalence of most vascular risk factors among ischemic stroke patients has increased in Native Americans over the last two decades. Significantly larger increases in hypertension and smoking prevalence were seen in Native Americans compared to other groups along with them having the highest prevalence in multiple risk factors in recent years.

Cigarette Smoking and Risk of Different Pathologic Types of Stroke: A Systematic Review and Dose-Response Meta-Analysis

Objectives

To quantify the association of cigarette smoking, including cigarettes per day and quitting duration, with the risk of different types of stroke morbidity and mortality in the general population, and to clarify the shape of the dose-response relations.

Study Selection

Prospective cohort studies and reported on the association between smoking, quitting and the incidence or mortality of stroke were included.

Data Extraction and Synthesis

All available data were converted uniformly to odds ratios (ORs) and were pooled using random-effects meta-analysis with inverse variance weighting. A dose-response meta-analysis was performed to explore the quantitative relationship between different smoking characteristics and the risk of different pathologic types of stroke incidence.

Results

Twenty-five studies with 3,734,216 individuals were included. Compared to never smokers, the pooled ORs of stroke morbidity and mortality were 1.45 (1.24–1.70) and 1.44 (1.23–1.67) among ever smokers and 1.90 (1.55–2.34) and 1.70 (1.45–1.98) among current smokers. The risk of different pathologic types of stroke was also increased among ever and current smokers. There was a significant non-linear dose-response association between the number of cigarette smoking and the risk of stroke incidence. Comparing no smoking, the ORs for smoking five and 35 cigarettes per day were 1.44 (1.35–1.53) and 1.86 (1.71–2.02). Other pathologic types of stroke have a similar dose-response relationship. There was also non-linear dose-response association between the length of time since quitting and risk of stroke. The risk of stroke decreased significantly after quitting for 3 years [OR = 0.56 (0.42–0.74)].

Conclusion

The risk of different types of stroke among smokers is remarkably high. Our findings revealed a more detailed dose-response relationship and have important implications for developing smoking control strategies for stroke prevention.

Systematic Review Registration

https://inplasy.com/inplasy-2020-6-0062/, identifier: INPLASY202060062.

[An overview of risk factors for stroke]

Stroke is a heterogeneous syndrome, and the definition of risk factors, treatment and prevention tactics depends on the specific pathogenesis of the disease. Risk factors for ischemic and hemorrhagic stroke are similar, but at the same time there are significant differences. The concept of stroke triggers is discussed separately. In addition, a deep understanding of the pathogenetic mechanisms and the development of new strategies for therapy and prevention require an understanding of the genetic mechanisms of stroke risk. Genetic factors may be more modifiable than previously thought. To reduce the burden of stroke in the population, timely identification and management of modifiable risk factors is essential.

Multi-level Diabetes Prevention and Treatment Interventions for Native People in the USA and Canada: a Scoping Review

PURPOSE OF REVIEW

This scoping literature review seeks to answer the question "What is known in the existing literature about multi-level diabetes prevention and treatment interventions for Native people living in the United States and Canada?"

RECENT FINDINGS

Multi-level interventions to prevent and/or treat chronic diseases, such as diabetes, promise to help individuals who experience health disparities related to social determinants of health. As described by the socio-ecological model, such interventions mobilize support through a combination of individual, interpersonal, organizational, community, and policy levels of activity. This review revealed little literature about multi-level diabetes prevention and/or treatment programs for US and Canada-based Native peoples. Ten interventions were identified; all focused on diabetes prevention; eight were specific to youth. Multi-level intervention design elements were largely individual-, school-, and community-based. Only three interventions included environmental or policy-level components.

Comparing Vascular Brain Injury and Stroke by Cranial Magnetic Resonance Imaging, Physician-Adjudication, and Self-Report: Data from the Strong Heart Study

BACKGROUND

Epidemiologic studies often use self-report as proxy for clinical history. However, whether self-report correctly identifies prevalence in minority populations with health disparities and poor health-care access is unknown. Furthermore, overlap of clinical vascular events with covert vascular brain injury (VBI), detected by imaging, is largely unexamined.

METHODS

The Strong Heart Study recruited American Indians from 3 regions, with surveillance and adjudication of stroke events from 1989 to 2013. In 2010-2013, all 817 survivors, aged 65-95 years, underwent brain imaging, neurological history interview, and cognitive testing. VBI was defined as imaged infarct or hemorrhage.

RESULTS

Adjudicated stroke was prevalent in 4% of participants and separately collected, self-reported stroke in 8%. Imaging-defined VBI was detected in 51% and not associated with any stroke event in 47%. Compared with adjudication, self-report had 76% sensitivity and 95% specificity. Participants with adjudicated or self-reported stroke had the poorest performance on cognitive testing; those with imaging-only (covert) VBI had intermediate performance.

CONCLUSION

In this community-based cohort, self-report for prior stroke had good performance metrics. A majority of participants with VBI did not have overt, clinically recognized events but did have neurological or cognitive symptoms. Data collection methodology for studies in a resource-limited setting must balance practical limitations in costs, accuracy, feasibility, and research goals.

Risk Factors in Adolescence for the Development of Elevated Blood Pressure and Hypertension in American Indian and Alaskan Native Adults

To examine risk factors for elevated blood pressure and hypertension in American Indians and Alaska Natives (AI/ANs), compared to three other ethnic groups in the US. Weighted relative risk regression models, stratified by race/ethnicity, were used to measure the associations between risk factors and elevated blood pressure and hypertension in AI/ANs, compared to non-Hispanic Whites, non-Hispanic Blacks and Hispanics, with data from the National Longitudinal Study of Adolescent to Adult Health. In all groups, females had a lower risk of both elevated blood pressure and hypertension than males. Increasing body mass index raised hypertension risk in all groups. In AI/ANs, financial instability increased the risk of hypertension by 88% (95% CI: 1.27-2.77), but not in other groups. No other statistically significant associations were found. Future interventions should include socio-economic factors in efforts to prevent hypertension in AI/ANs.

Food Insecurity and Associated Challenges to Healthy Eating Among American Indians and Alaska Natives With Type 2 Diabetes: Multiple Stakeholder Perspectives

Objective: To examine stakeholder perspectives on food insecurity and associated challenges to healthy eating among American Indian and Alaska Native (AI/AN) adults with type 2 diabetes (T2D). Methods: Focus groups and interviews were conducted with purposively selected stakeholders: AI/ANs with T2D, their family members, healthcare administrators, nutrition and diabetes educators, and national content experts on AI/AN health. Two coders analyzed transcripts using the constant-comparison method. Results: Key themes included (1) rural- and urban-dwelling AI/ANs experience different primary food security and associated challenges; (2) factors contributing to food insecurity extend beyond cost of healthy food; and (3) barriers to consuming fresh, healthy food include cost, preparation time, limited cooking knowledge, and challenges with gardening. Discussion: Resources for AI/ANs with T2D who experience food insecurity and associated challenges to healthy eating should be tailored based on urban versus rural location and should address cost and other barriers to consumption of fresh fruits and vegetables.

A systematic review of psychosocial interventions for Latinx and American Indian patient-family caregiver dyads coping with chronic health conditions

Latinx and American Indians experience high rates of chronic health conditions. Family members play a significant role as informal caregivers for loved ones with chronic conditions and both patients and family caregivers report poor psychosocial outcomes. This systematic review synthesizes published studies about psychosocial interventions for Latinx and American Indian care dyads to determine: (i) the benefits of these interventions; (ii) their distinguishing features or adaptations, and; (iii) recommendations for future intervention development. Out of 366 records identified, seven studies met inclusion criteria. Interventions demonstrated benefits to outcomes such as disease knowledge, caregiver self-efficacy and burden, patient and caregiver well-being, symptom distress, anxiety and depression, and dyadic communication. Distinguishing features included tailoring to cultural values, beliefs, and delivery preferences, participants' level of acculturation, and population-specific issues such as migratory stressors and support networks. Based upon this review, six recommendations for future intervention development are put forth.

U.S. Population-Based background incidence rates of medical conditions for use in safety assessment of COVID-19 vaccines

The Coronavirus Disease 2019 (COVID-19) pandemic has had a devastating impact on global health, and has resulted in an unprecedented, international collaborative effort to develop vaccines to control the outbreak, protect human lives, and avoid further social and economic disruption. Mass vaccination campaigns are underway in multiple countries and are expected worldwide once more vaccine becomes available. Some early candidate vaccines use novel platforms, such as mRNA encapsulated in lipid nanoparticles, and relatively new platforms, such as replication-deficient viral vectors. While these new vaccine platforms hold promise, limited safety data in humans are available. Serious health outcomes linked to vaccinations are rare, and some outcomes may occur incidentally in the vaccinated population. Knowledge of background incidence rates of these medical conditions is a critical component of vaccine safety monitoring to aid in the assessment of adverse events temporally associated with vaccination and to put these events into context with what would be expected due to chance alone. A list of 22 potential adverse events of special interest (AESI), including neurologic, autoimmune, and cardiovascular disorders, was compiled by subject matter experts at the U.S. Food and Drug Administration and the Centers for Disease Control and Prevention. The most recently available U.S. background rates for these medical conditions, overall and by age, sex, and race/ethnicity (when available), were sourced from reported statistics (data published by medical panels/ associations or federal government reports), and literature reviews in PubMed. This review provides estimates of background incidence rates for medical conditions that may be monitored or studied as AESI during safety surveillance and research for COVID-19 vaccines and other new vaccines.

The Incidence of Stroke in Indigenous Populations of Countries With a Very High Human Development Index: A Systematic Review Protocol

Background and Aims: Despite known Indigenous health and socioeconomic disadvantage in countries with a Very High Human Development Index, data on the incidence of stroke in these populations are sparse. With oversight from an Indigenous Advisory Board, we will undertake a systematic review of the incidence of stroke in Indigenous populations of developed countries or regions, with comparisons between Indigenous and non-Indigenous populations of the same region, though not between different Indigenous populations. Methods: Using PubMed, OVID-EMBASE, and Global Health databases, we will examine population-based incidence studies of stroke in Indigenous adult populations of developed countries published 1990-current, without language restriction. Non-peer-reviewed sources, studies including <10 Indigenous People, or with insufficient data to determine incidence, will be excluded. Two reviewers will independently validate the search strategies, screen titles and abstracts, and record reasons for rejection. Relevant articles will undergo full-text screening, with standard data extracted for all studies included. Quality assessment will include Sudlow and Warlow's criteria for population-based stroke incidence studies, the Newcastle-Ottawa Scale for risk of bias, and the CONSIDER checklist for Indigenous research. Results: Primary outcomes include crude, age-specific and/or age-standardized incidence of stroke. Secondary outcomes include overall stroke rates, incidence rate ratio and case-fatality. Results will be synthesized in figures and tables, describing data sources, populations, methodology, and findings. Within-population meta-analysis will be performed if, and where, methodologically sound and comparable studies allow this. Conclusion: We will undertake the first systematic review assessing disparities in stroke incidence in Indigenous populations of developed countries. Data outputs will be disseminated to relevant Indigenous stakeholders to inform public health and policy research.

Gender differences in the assessment of depression in American Indian older adults: The Strong Heart Study

The validation of the assessment of depression across ethnic groups is critical yet deficient for American Indian (AI) adults. Therefore, we assessed the psychometric properties of the Center for Epidemiological Studies-Depression (CES-D) in AI elders and tested differences in depression constructs between gender. Participants were 817 AI adults (68% women), mean age 73.2 years (SD = 6.1, range: 64-95) for women and 72.6 years (SD = 5.3, range: 65-90) for men., in the Cerebrovascular Disease and Its Consequences in AIs Study. We evaluated the factor structure of the 20-item and 12-item CES-D and tested measurement invariance between gender. Results demonstrated a poor fit for the 20-item CES-D and partial gender measurement invariance of the 12-item CES-D. AI female elders had significantly higher depression levels than AI male elders on the Depressed Affect subscale, the Somatic Symptoms subscale, and the Well-Being (reverse-coded) subscale. Further replication is needed, and we recommend future psychometric work with the 12-item CES-D with AI elders. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Incident Strokes Among American Indian Individuals With Atrial Fibrillation

BACKGROUND

American Indian individuals experience a relatively high risk for cardiovascular disease and have exhibited a higher risk of stroke compared with other racial and ethnic minorities. Although this population has the highest incidence of atrial fibrillation (AF) compared with other groups, the relationship between AF and nonhemorrhagic stroke among American Indian individuals compared with other groups has not been thoroughly studied.

METHODS and RESULTS

We used the Healthcare Cost and Utilization Project to evaluate risk of nonhemorrhagic stroke among American Indian individuals, with comparisons to White, Black, Hispanic, and Asian individuals, among all adult California residents receiving care in an emergency department, inpatient hospital unit, or ambulatory surgery setting from 2005 to 2011. Of 16 951 579 patients followed for a median 4.1 years, 105 822 (0.6%) were American Indian. After adjusting for age, sex, income level, insurance payer, hypertension, diabetes mellitus, coronary artery disease, congestive heart failure, cardiac surgery, valvular heart disease, chronic kidney disease, smoking, obstructive sleep apnea, pulmonary disease, and alcohol use, American Indian individuals with AF exhibited the highest risk of nonhemorrhagic stroke when compared with either non‐American Indian individuals with AF (hazard ratio, 1.38; 95% CI, 1.23–1.55; P<0.0001) or to each race and ethnicity with AF. American Indian individuals also experienced the highest overall risk for stroke, with no evidence that AF disproportionately heightened that risk in interaction analyses.

CONCLUSIONS

American Indian individuals experienced the highest risk of nonhemorrhagic stroke, whether in the presence or absence of AF. Our findings likely suggest an opportunity to further study, if not immediately address, guideline‐adherent anticoagulation prescribing patterns among American Indian individuals with AF.

Associations of Binge Drinking With Vascular Brain Injury and Atrophy in Older American Indians: The Strong Heart Study

Objectives: American Indians (AIs) generally consume less alcohol than the US general population; however, the prevalence of alcohol use disorder is higher. This is the first large cohort study to examine binge drinking as a risk factor for vascular brain injury (VBI). Methods: We used linear and Poisson regression to examine the association of self-reported binge drinking with VBI, measured via magnetic resonance imaging (MRI), in 817 older AIs who participated in the Strong Heart and Cerebrovascular Disease and Its Consequences in American Indians studies. Results: Any binge drinking at multiple time-points was associated with increased sulcal (β = 0.360, 95% CI [0.079, 0.641]) and ventricle dilatation (β = 0.512, 95% CI [0.174, 0.850]) compared to no binge drinking. Discussion: These observed associations are consistent with previous findings. Identifying how binge drinking may contribute to VBI in older AIs may suggest modifiable health behaviors for neurological risk reduction and disease prevention.

Glomerular filtration function decline, mortality, and cardiovascular events: data from the Strong Heart Study

BACKGROUND

Rapid kidney decline is associated with mortality and cardiovascular disease, even in the absence of chronic kidney disease. American Indians (AI) have particularly high burden of kidney disease, cardiovascular disease, and stroke. This study aims to examine extreme loss in glomerular function in this population in association with clinical outcomes.

METHODS

The Strong Heart Study, a large longitudinal cohort of adult AI participants, collected plasma creatinine at 3 examination visits between 1989-1999. Intraindividual regressions of estimated glomerular filtration rate (eGFR) provided linear estimates of change in kidney function over this time period. Surveillance with physician adjudication identified mortality and cardiovascular events between visit 3 through 2017.

RESULTS

Mean change in eGFR was loss 6.8 mL/min over the ten year baseline (range: -66.0 to +28.9 mL/min). The top 1 percentile lost approximately 5.7 mL/min/year. Participants with extreme eGFR loss were more likely to have diabetes (95% vs 71%), hypertension (49% vs 33%), or longer smoking history, among smokers (19 pack years vs 17 pack years). CKD (eGFR<60 mL/min) was associated only with mortality, independent of slope: HR 1.1 (95% CI 1.0-1.3). However, extreme loss in eGFR (>20 mL/min over baseline period) was associated with mortality, independent of baseline eGFR: HR 3.5 (95% CI 2.7-4.4), and also independently associated with composite CVD events and CHF: HR 1.4 and 1.7 (95% CI 1.1-1.9 and 1.2-2.6), respectively.

CONCLUSION

This is the first examination of decline in eGFR in association with mortality and CVD among AIs. The implications of these findings are broad: clinical evaluation may benefit from evaluating change in eGFR over time in addition to dichotomous eGFR. Also, these findings suggest there may be aspects of renal function that are not well-marked by clinical CKD, but which may have particular relevance to long-term renal and vascular health.

Inaugural Health Equity and Actionable Disparities in Stroke: Understanding and Problem-Solving Symposium

Race/ethnic minorities face significant inequities in stroke incidence, prevalence, care, and outcomes. The Health Equity and Actionable Disparities in Stroke: Understanding and Problem-solving symposium, a collaborative initiative of the American Heart Association and National Institute of Neurological Disorders and Stroke, was the first-ever annual multidisciplinary scientific forum focused on race/ethnic inequities in cerebrovascular disease, with the overarching goal of reducing inequities in stroke and accelerating the translation of research findings to improve outcomes for race/ethnic minorities. The symposium featured esteemed invited plenary speakers, lecturing on determinants of race/ethnic inequities in stroke and interventions aimed at redressing the inequities. The Edgar J. Kenton III Award recognized Ralph Sacco, MD, MS, for his lifetime contributions to investigation, management, mentorship, and community service in the field of stroke inequities. Early career investigators were provided with travel awards to attend the symposium; presented their research at moderated poster and Think Tank sessions; received career development advice at the Building Momentum session; and networked with experienced stroke inequities researchers. Future conferences-The Health Equity and Actionable Disparities in Stroke: Understanding and Problem-solving 2021 to 2024-will broaden the focus to include 5 major persistent inequities (race/ethnic, sex, geographic, socioeconomic, and global). Each year will focus on a different theme (community and stakeholder engagement; clinical trials; implementation science; and policy and dissemination). By fostering a community of stroke inequities researchers, we hope to highlight promising work, illuminate research gaps, facilitate networking, inform policy makers, recognize achievement, inspire greater interest among junior investigators to pursue careers in this field, and provide networking opportunities for underrepresented minority scientists.

Prehypertension and risk of cardiovascular diseases: a meta-analysis of 47 cohort studies

OBJECTIVE

To assess the association of prehypertension (SBP 120-139 mmHg and/or DBP 80-89 mmHg) and total cardiovascular diseases (CVDs), coronary heart disease (CHD), myocardial infarction (MI), and stroke.

METHODS

PubMed, Embase, and Web of Science were searched for articles published up to 7 November 2018. Normal range BP was considered SBP less than 120 mmHg and DBP less than 80 mmHg. RRs and 95% CIs were pooled using fixed-effects models. Meta-regression was conducted to estimate the heterogeneity among subgroups.

RESULTS

We included 27 articles (47 studies including 491 666 study participants) in the analysis. Prehypertension was associated with total CVDs (RR 1.40, 95% CI 1.34-1.46), CHD (1.40, 1.28-1.52), MI (1.86, 1.50-2.32), and stroke (1.66, 1.56-1.76). Risk of total CVDs, MI, and stroke was increased with low-range prehypertension (low-range: SBP 120-129 mmHg and/or DBP 80-84 mmHg) versus normal BP - RR 1.42 (95% CI 1.29-1.55), 1.43 (1.10-1.86), and 1.52 (1.27-1.81), respectively - and risk of total CVDs, CHD, MI, and stroke was increased with high-range prehypertension (high-range: SBP 130-139 mmHg and/or DBP 85-89 mmHg) - RR 1.81 (95% CI 1.56-2.10), 1.65 (1.13-2.39), 1.99 (1.59-2.50), and 1.99 (1.68-2.36), respectively. The population-attributable risk for the association of total CVDs, CHD, MI, and stroke with prehypertension was 12.09, 13.26, 24.60, and 19.15%, respectively.

CONCLUSION

Prehypertension, particularly high-range, is associated with increased risk of total CVDs, CHD, MI, and stroke. Effective control of prehypertension could prevent more than 10% of CVD cases.

Cigarette Smoking and Incident Stroke in Blacks of the Jackson Heart Study

Background Blacks are disproportionately affected by stroke compared with whites; however, less is known about the relationship between stroke and cigarette smoking in blacks. Therefore, we evaluated the relationship between cigarette smoking and all incident stroke in the JHS (Jackson Heart Study). Methods and Results JHS participants without a history of stroke (n=4410) were classified by self-reported baseline smoking status into current, past (smoked at least 400 cigarettes/life), or never smokers at baseline (2000-2004). Current smokers were further classified by smoking intensity (number of cigarettes smoked per day [1-19 and ≥20]) and followed up for incident stroke (through 2015). Hazard ratios (HRs) for incident stroke for current and past smoking compared with never smoking were estimated with adjusted Cox proportional hazard regression models. After adjusting for cardiovascular risk factors, the risk for stroke in current smokers was significantly higher compared with never smokers (HR, 2.48; 95% CI, 1.60-3.83) but there was no significant difference between past smokers and never smokers (HR, 1.10; 95% CI, 0.74-1.64). There was a dose-dependent increased risk of stroke with smoking intensity (HR, 2.28 [95% CI, 1.38-3.86] and HR, 2.78 [95% CI, 1.47-5.28] for current smokers smoking 1-19 and ≥20 cigarettes/day, respectively). Conclusions In a large cohort of blacks, current cigarette smoking was associated with a dose-dependent higher risk of all stroke. In addition, past smokers did not have a significantly increased risk of all stroke compared with never smokers, which suggests that smoking cessation may have potential benefits in reducing the incidence of stroke in blacks.

Cognitive Correlates of MRI-defined Cerebral Vascular Injury and Atrophy in Elderly American Indians: The Strong Heart Study

OBJECTIVE

American Indians experience substantial health disparities relative to the US population, including vascular brain aging. Poorer cognitive test performance has been associated with cranial magnetic resonance imaging findings in aging community populations, but no study has investigated these associations in elderly American Indians.

METHODS

We examined 786 American Indians aged 64 years and older from the Cerebrovascular Disease and its Consequences in American Indians study (2010-2013). Cranial magnetic resonance images were scored for cortical and subcortical infarcts, hemorrhages, severity of white matter disease, sulcal widening, ventricle enlargement, and volumetric estimates for white matter hyperintensities (WMHs), hippocampus, and brain. Participants completed demographic, medical history, and neuropsychological assessments including testing for general cognitive functioning, verbal learning and memory, processing speed, phonemic fluency, and executive function.

RESULTS

Processing speed was independently associated with the presence of any infarcts, white matter disease, and hippocampal and brain volumes, independent of socioeconomic, language, education, and clinical factors. Other significant associations included general cognitive functioning with hippocampal volume. Nonsignificant, marginal associations included general cognition with WMH and brain volume; verbal memory with hippocampal volume; verbal fluency and executive function with brain volume; and processing speed with ventricle enlargement.

CONCLUSIONS

Brain-cognition associations found in this study of elderly American Indians are similar to those found in other racial/ethnic populations, with processing speed comprising an especially strong correlate of cerebrovascular disease. These findings may assist future efforts to define opportunities for disease prevention, to conduct research on diagnostic and normative standards, and to guide clinical evaluation of this underserved and overburdened population.

Heart Disease and Stroke Statistics-2020 Update: A Report From the American Heart Association

BACKGROUND

The American Heart Association, in conjunction with the National Institutes of Health, annually reports on the most up-to-date statistics related to heart disease, stroke, and cardiovascular risk factors, including core health behaviors (smoking, physical activity, diet, and weight) and health factors (cholesterol, blood pressure, and glucose control) that contribute to cardiovascular health. The Statistical Update presents the latest data on a range of major clinical heart and circulatory disease conditions (including stroke, congenital heart disease, rhythm disorders, subclinical atherosclerosis, coronary heart disease, heart failure, valvular disease, venous disease, and peripheral artery disease) and the associated outcomes (including quality of care, procedures, and economic costs).

METHODS

The American Heart Association, through its Statistics Committee, continuously monitors and evaluates sources of data on heart disease and stroke in the United States to provide the most current information available in the annual Statistical Update. The 2020 Statistical Update is the product of a full year's worth of effort by dedicated volunteer clinicians and scientists, committed government professionals, and American Heart Association staff members. This year's edition includes data on the monitoring and benefits of cardiovascular health in the population, metrics to assess and monitor healthy diets, an enhanced focus on social determinants of health, a focus on the global burden of cardiovascular disease, and further evidence-based approaches to changing behaviors, implementation strategies, and implications of the American Heart Association's 2020 Impact Goals.

RESULTS

Each of the 26 chapters in the Statistical Update focuses on a different topic related to heart disease and stroke statistics.

CONCLUSIONS

The Statistical Update represents a critical resource for the lay public, policy makers, media professionals, clinicians, healthcare administrators, researchers, health advocates, and others seeking the best available data on these factors and conditions.

Trends in Cardiovascular Disease Morbidity and Mortality in American Indians Over 25 Years: The Strong Heart Study

Background American Indians experience high rates of cardiovascular disease. We evaluated whether cardiovascular disease incidence, mortality, and prevalence changed over 25 years among American Indians aged 30 to 85. Methods and Results The SHS (Strong Heart Study) and SHFS (Strong Heart Family Study) are prospective studies of cardiovascular disease in American Indians. Participants enrolled in 1989 to 1990 or 2000 to 2003 with birth years from 1915 to 1984 were followed for cardiovascular disease events through 2013. We used Poisson regression to analyze data for 5627 individuals aged 30 to 85 years during follow-up. Outcomes reflect change in age-specific cardiovascular disease incidence, mortality, and prevalence, stratified by sex. To illustrate generational change, 5-year relative risk compared most recent birth years for ages 45, 55, 65, and 75 to same-aged counterparts born 1 generation (23-25 years) earlier. At all ages, cardiovascular disease incidence was lower for people with more recent birth years. Cardiovascular disease mortality declined consistently among men, while prevalence declined among women. Generational comparisons were similar for women aged 45 to 75 (relative risk, 0.39-0.46), but among men magnitudes strengthened from age 45 to 75 (relative risk, 0.91-0.39). For cardiovascular disease mortality, risk was lower in the most recent versus the earliest birth years for women (relative risk, 0.56-0.83) and men (relative risk, 0.40-0.54), but results for women were inconclusive. Conclusions Cardiovascular disease incidence declined over a generation in an American Indian cohort. Mortality declined more for men, while prevalence declined more for women. These trends might reflect more improvement in case survival among men compared with women.

Stroke Incidence and Survival in American Indians, Blacks, and Whites: The Strong Heart Study and Atherosclerosis Risk in Communities Study

Background

American Indians (AIs) have high stroke morbidity and mortality. We compared stroke incidence and mortality in AIs, blacks, and whites.

Methods and Results

Pooled data from 2 cardiovascular disease cohort studies included 3182 AIs from the SHS (Strong Heart Study), aged 45 to 74 years at baseline (1988–1990) and 3765 blacks and 10 413 whites from the ARIC (Atherosclerosis Risk in Communities) Study, aged 45 to 64 years at baseline (1987–1989). Stroke surveillance was based on self‐report, hospital records, and death certificates. We estimated hazard ratios for incident stroke (ischemic and hemorrhagic combined) through 2008, stratified by sex and birth‐year tertile, and relative risk for poststroke mortality. Incident strokes numbered 282 for AIs, 416 for blacks, and 613 for whites. For women and men, stroke incidence among AIs was similar to or lower than blacks and higher than whites. Covariate adjustment resulted in lower hazard ratios for most comparisons, but results for these models were not always statistically significant. After covariate adjustment, AI women and men had higher 30‐day poststroke mortality than blacks (relative risk=2.1 [95% CI=1.0, 3.2] and 2.2 [95% CI=1.3, 3.1], respectively), and whites (relative risk=1.6 [95% CI=0.8, 2.5] and 1.7 [95% CI=1.1, 2.4]), and higher 1‐year mortality (relative risk range=1.3–1.5 for all comparisons).

Conclusions

Stroke incidence in AIs was lower than for blacks and higher than for whites; differences were larger for blacks and smaller for whites after covariate adjustment. Poststroke mortality was higher in AIs than blacks and whites.

Lifestyle Risk Factors and Findings on Brain Magnetic Resonance Imaging of Older Adult American Indians: The Strong Heart Study

BACKGROUND

Clinical stroke is prevalent in American Indians, but the lifestyle risk factors for vascular brain injury have not been well-studied in this population. The purpose of this study was to correlate brain magnetic resonance imaging (MRI) findings with obesity, alcohol use, and smoking behaviors in elderly American Indians from the Strong Heart Study.

METHODS

Cranial MRI scans (n = 789) were analyzed for dichotomous measures of infarcts, hemorrhages, white matter hyperintensities (WMH), and cerebral atrophy and continuous measures of total brain, WMH, and hippocampal volume. Poisson regression was used to estimate prevalence ratios, and linear regression was used to estimate measures of association for continuous outcomes. Models were adjusted for the risk factors of interest as well as age, sex, study site, income, education, hypertension, diabetes, and low-density lipoprotein cholesterol.

RESULTS

Smoking was associated with increased hippocampal atrophy (p = 0.002) and increased prevalence of sulcal widening (p < 0.001). Relative to nonsmokers, smokers with more than 25 pack-years of smoking had a 27% (95% CI 7-47%) increased prevalence of high-grade sulci, p = 0.005. Body mass index was inversely associated with prevalence of nonlacunar infarcts and sulcal widening (all p = 0.004). Alcohol use was not significantly associated with any of the measured MRI findings.

CONCLUSIONS

This study found similar associations between smoking and vascular brain injury among American Indians, as seen in other populations. In particular, these findings support the role of smoking as a key correlate for cerebral atrophy.

Vascular Risk Factors and Findings on Brain MRI of Elderly Adult American Indians: The Strong Heart Study

BACKGROUND

Clinical stroke is prevalent in American Indians, but the risk factors for cerebrovascular pathology have not been well-studied in this population. The purpose of this study was to correlate abnormalities on brain magnetic resonance imaging (MRI) with clinical risk factors in a cohort of elderly American Indians.

METHODS

Brain MRI scans from 789 participants of the Strong Heart Study were analyzed for infarcts, hemorrhage, white matter disease, and measures of cerebral atrophy including ventricular and sulcal grade and total brain volume. Clinical risk factors included measures of hypertension, diabetes, and high levels of low-density lipoprotein (LDL) cholesterol. Regression models adjusted for potential confounders were used to estimate associations between risk factors and brain MRI outcomes.

RESULTS

-Hypertension was associated with the presence of infarcts (p = 0.001), ventricle enlargement (p = 0.01), and increased white matter hyperintensity volume (p = 0.01). Diabetes was associated with increased prevalence of cerebral atrophy (p < 0.001), ventricular enlargement (p = 0.001), and sulcal widening (p = 0.001). High LDL was not significantly associated with any of the measured cranial imaging outcomes.

CONCLUSIONS

This study found risk factors for cerebrovascular disease in American Indians similar to those seen in other populations and provides additional evidence for the important roles of hypertension and diabetes in promoting cerebral infarcts and brain atrophy, respectively.

"Improving Native American elder access to and use of health care through effective health system navigation"

BACKGROUND

Public insurance reforms of the past two decades have failed to substantively address the healthcare needs of American Indians in general, let alone the particular needs of American Indian elders, ages 55 years and older. Historically, this population is more likely to be uninsured and to suffer from greater morbidities, poorer health outcomes and quality of life, and lower life expectancies compared to all other United States aging populations, representing a neglected group within the healthcare system. Despite the pervasive belief that the Indian Health Service will address all their health-related needs, American Indian elders are negatively affected by gaps in insurance and lack of access to health care. While the 2010 Patient Protection and Affordable Care Act included provisions to ameliorate disparities for American Indians, its future is uncertain. In this context, American Indian elders with variable health literacy must navigate a complex and unstable healthcare system, regardless of where they seek care.

METHODS

This community-driven study features a mixed-method, participatory design to examine help-seeking behavior and healthcare experiences of American Indian elders in New Mexico, in order to develop and evaluate a tailored intervention to enhance knowledge of, access to, and use of insurance and available services to reduce healthcare disparities. This study includes qualitative and quantitative interviews combined with concept mapping and focus groups with American Indian elders and other key stakeholders.

DISCUSSION

The information gathered will generate new practical knowledge, grounded in actual perspectives of American Indian elders and other relevant stakeholders, to improve healthcare practices and policies for a population that has been largely excluded from national and state discussions of healthcare reform. Study data will inform development and evaluation of culturally tailored programming to enhance understanding and facilitate negotiation of the changing landscape of health care by American Indian elders. This work will fill a gap in research on public insurance initiatives, which do not typically focus on this population, and will offer a replicable model for enhancing the effects of such initiatives on other underserved groups affected by healthcare inequities.

TRIAL REGISTRATION

This protocol does not include the collection of health outcome data. Clinicaltrials.gov, NCT03550404 . Registered June 6, 2018.

Association between urinary sodium excretion and uric acid, and its interaction on the risk of prehypertension among Chinese young adults

High uric acid (UA) level and high salt intake are reportedly associated with cardiovascular disease. This study investigated the association between UA and urinary sodium excretion, as well as its interaction on the risk of prehypertension. A total of 1869 participants without hypertension were recruited from a previously established cohort in Shaanxi Province, China. The participants were classified as normotensive or prehypertensive on the basis of their blood pressure. Increasing quartiles of sodium excretion were associated with high urinary UA/creatinine levels in prehypertensive participants. Estimated sodium excretion positively correlated with urinary UA/creatinine excretions in the prehypertensive group. In addition, the multivariate-adjusted odds ratios for prehypertension compared with normotension were 1.68 (1.27–2.22) for sodium excretion and 1.71 (1.21–2.42) for serum UA. Increasing sodium excretion and serum UA were associated with higher risk of prehypertension. Compared with the lowest quartiles, the highest sodium excretion and serum UA quartiles entailed 3.48 times greater risk of prehypertension. Sodium excretion is associated with urinary UA excretion in prehypertensive participants. The present study shows that high levels of salt intake and serum UA simultaneously are associated with a higher risk of prehypertension.

Relationship Between Glycated Hemoglobin and Stroke Risk: A Systematic Review and Meta-Analysis

BACKGROUND

Diabetes mellitus is a major risk factor for ischemic stroke. Rising hemoglobin A_1c (HbA_1c) levels are associated with microvascular diabetes mellitus complication development; however, this relationship has not been established for stroke risk, a macrovascular complication.

METHODS AND RESULTS

We conducted a systematic review and meta-analysis of observational cohort and nested case-control cohort studies assessing the association between rising HbA_1c levels and stroke risk in adults (≥18 years old) with and without type 1 or type 2 diabetes mellitus. Random-effects model meta-analyses were used to calculate pooled adjusted hazard ratios (HRs) and their precision. The systematic review yielded 36 articles, of which 29 articles (comprising n=532 779 participants) were included in our meta-analysis. Compared to non-diabetes mellitus range HbA_1c (<5.7%), diabetes mellitus range HbA_1c (≥6.5%) was associated with an increased risk of first-ever stroke with average HR (95% confidence interval) of 2.15 (1.76, 2.63), whereas pre-diabetes mellitus range HbA_1c (5.7-6.5%) was not (average HR [95% confidence interval], 1.19 [0.87, 1.62]). For every 1% HbA_1c increment (or equivalent), the average HR (95% confidence interval) for first-ever stroke was 1.12 (0.91, 1.39) in non-diabetes mellitus cohorts and 1.17 (1.09, 1.25) in diabetes mellitus cohorts. For every 1% HbA_1c increment, both non-diabetes mellitus and diabetes mellitus cohorts had a higher associated risk of first-ever ischemic stroke with average HR (95% confidence interval) of 1.49 (1.32, 1.69) and 1.24 (1.11, 1.39), respectively.

CONCLUSIONS

A rising HbA_1c level is associated with increased first-ever stroke risk in cohorts with a diabetes mellitus diagnosis and increased risk of first-ever ischemic stroke in non-diabetes mellitus cohorts. These findings suggest that more intensive HbA_1c glycemic control targets may be required for optimal ischemic stroke prevention.

Joint effects of OSA and self-reported sleepiness on incident CHD and stroke

BACKGROUND

Although excessive daytime sleepiness (EDS) is a common symptom of obstructive sleep apnea (OSA), and both EDS and OSA have separately been associated with increased risk of cardiovascular disease (CVD), their joint association with CVD risk is unknown.

METHODS

Among 3874 Sleep Heart Health Study (SHHS) participants without prevalent CVD, moderate to severe OSA was defined by an apnea hypopnea index (AHI) ≥ 15 on an in-home polysomnography. EDS was defined as an Epworth Sleepiness Scale score ≥11. Incident CVD events included total CVD events (coronary heart disease (CHD) and stroke), as well as CHD and stroke separately. Cox proportional hazards models adjusted for age, sex, alcohol, smoking, and body mass index.

RESULTS

Compared to those with AHI <15, the hazard ratios (95% CI) for the association of moderate-severe OSA (AHI ≥15) were as follows: CVD 1.06 (0.85-1.33); CHD 1.08 (0.85-1.33); and stroke 1.18 (0.75-1.84). Weak associations between EDS and CVD risk = [1.22 (1.01-1.47)] and CHD risk [1.25 (1.02-1.53)] were present, however there were none for stroke risk [1.10 (0.75-1.63)]. When jointly modeled, both AHI ≥15 and EDS (compared with having AHI <15 and no EDS) was associated with HRs of 1.26 (0.91-1.73) for CVD, 1.24 (0.87-1.75) for CHD and 1.49 (0.78-2.86) for stroke. There were no statistically significant interactions between daytime sleepiness and OSA on the multiplicative or additive scales.

CONCLUSIONS

Having both EDS and moderate-severe OSA was not associated with an increased risk of CVD in the SHHS data.

Diabetes and Associated Cardiovascular Complications in American Indians/Alaskan Natives: A Review of Risks and Prevention Strategies

Diabetes mellitus (DM) is the seventh leading cause of death in the United States and the leading cause of death in the U.S. American Indian/Alaskan Natives (AI/ANs), who comprise only 2% of the total population. The AI/AN population has a high prevalence of DM in adults aged 20 years or older and is developing DM at a younger age than the general U.S.

POPULATION

DM is a major risk factor for cardiovascular disease (CVD), and mortality from CVD is higher in AI/ANs than the general population, as is the prevalence of stroke and 1-year poststroke mortality for both genders when compared to non-Hispanic whites. A genome-wide scan found a number of chromosome linkages in the AI/AN population that suggest that genetic factors may contribute to their high risk of DM and CVD. Importantly, studies also suggest that in addition to race/ethnicity, cultural norms and historic conditions play important roles in the prevalence of DM and CVD in this population. Therefore, multiple factors should be taken into consideration when establishing prevention programs to decrease the prevalence of obesity, diabetes, and CVD incidence among adults and children in the AI/AN population. Prevention programs should focus on behavioral risk factors and lifestyle changes like encouraging smoking cessation, healthy diet, and increased physical activity while taking into consideration cultural, economic, and geographic factors.

Smoking, Hypertension, and Their Combined Effect on Ischemic Stroke Incidence: A Prospective Study among Inner Mongolians in China

OBJECTIVE

We intended to investigate the combined effect of smoking and hypertension on ischemic stroke incidence based on a 10-year prospective study among Inner Mongolians in China.

METHODS

A prospective cohort study from June 2003 to July 2012 was conducted among 2589 participants aged 20 years and older from Inner Mongolia, China. We categorized the participants into 4 subgroups according to the status of smoking and hypertension. The cumulative incidence rates of ischemic stroke among the 4 subgroups were estimated using Kaplan-Meier curves and compared by log-rank test. Cox proportional hazard model was used to compute hazard ratios of ischemic stroke across the 4 subgroups after adjusting for important confounding factors.

RESULTS

The cumulative incidence rates of ischemic stroke were .85%, 2.05%, 3.19%, and 8.14% among non-hypertension/non-smokers, non-hypertension/smokers, hypertension/non-smokers, and hypertension/smokers, respectively. The multivariable-adjusted hazard ratios [95% confidence intervals] of ischemic stroke for hypertension and smoking were 1.84 [1.05-3.23] and 1.89 [1.11-3.22], respectively. The hazard ratios [95% confidence intervals] of ischemic stroke for non-hypertension/smokers, hypertension/non-smokers, and hypertension/smokers were 1.37 [.56-3.33], 1.34 [.54-3.29], and 2.93 [1.26-6.83], respectively, compared with the non-hypertension/non-smokers. Significant interaction was detected between smoking and hypertension on the risk of ischemic stroke.

CONCLUSIONS

Our study indicated that participants with coexistence of smoking and hypertension were at the highest risk for ischemic stroke. There was a significant interaction between smoking and hypertension on the risk of ischemic stroke.

Risk Factors and Prediction of Stroke in a Population with High Prevalence of Diabetes: The Strong Heart Study

BACKGROUND AND OBJECTIVE

American Indians have a high prevalence of diabetes and higher incidence of stroke than that of whites and blacks in the U.S. Stroke risk prediction models based on data from American Indians would be of clinical and public health value.

METHODS AND RESULTS

A total of 3483 (2043 women) Strong Heart Study participants free of stroke at baseline were followed from 1989 to 2010 for incident stroke. Overall, 297 stroke cases (179 women) were identified. Cox models with stroke-free time and risk factors recorded at baseline were used to develop stroke risk prediction models. Assessment of the developed stroke risk prediction models regarding discrimination and calibration was performed by an analogous C-statistic (C) and a version of the Hosmer-Lemeshow statistic (HL), respectively, and validated internally through use of Bootstrapping methods.

RESULTS

Age, smoking status, alcohol consumption, waist circumference, hypertension status, an-tihypertensive therapy, fasting plasma glucose, diabetes medications, high/low density lipoproteins, urinary albumin/creatinine ratio, history of coronary heart disease/heart failure, atrial fibrillation, or Left ventricular hypertrophy, and parental history of stroke were identified as the significant optimal risk factors for incident stroke.

DISCUSSION

The models produced a C = 0.761 and HL = 4.668 (p = 0.792) for women, and a C = 0.765 and HL = 9.171 (p = 0.328) for men, showing good discrimination and calibration.

CONCLUSIONS

Our stroke risk prediction models provide a mechanism for stroke risk assessment designed for American Indians. The models may be also useful to other populations with high prevalence of obesity and/or diabetes for screening individuals for risk of incident stroke and designing prevention programs.

Triglyceride and HDL-C Dyslipidemia and Risks of Coronary Heart Disease and Ischemic Stroke by Glycemic Dysregulation Status: The Strong Heart Study

OBJECTIVE

High triglyceride (TG) levels and low HDL cholesterol (HDL-C) levels are risk factors for cardiovascular disease. It is unclear whether this relationship depends on glycemic dysregulation, sex, or LDL cholesterol (LDL-C) level.

RESEARCH DESIGN AND METHODS

We studied 3,216 participants (40% men, 41% with diabetes) who were free of cardiovascular disease at baseline in a community-based, prospective cohort of American Indians (median follow-up 17.7 years). Cox models estimated hazard ratios (HRs) and 95% CIs for incident ischemic stroke and coronary heart disease (CHD) in relation to combined TG and HDL-C status, where a fasting TG level ≥150 mg/dL was "high" and a fasting HDL-C level <40 mg/dL for men (<50 mg/dL for women) was "low." Models included age, sex, BMI, smoking, diabetes, fasting LDL-C level, antihypertensive medications, physical activity, estimated glomerular filtration rate, and urinary albumin-to-creatinine ratio.

RESULTS

Participants with high TG and low HDL levels had a 1.32-fold greater HR (95% CI 1.06-1.64) for CHD than those with normal TG and normal HDL levels. It was observed in participants with diabetes, but not in those without diabetes, that high TG plus low HDL levels were associated with a 1.54-fold greater HR (95% CI 1.15-2.06) for CHD (P value for interaction = 0.003) and a 2.13-fold greater HR (95% CI 1.06-4.29) for stroke (P value for interaction = 0.060). High TG and low HDL level was associated with CHD risk in participants with an LDL-C level of ≥130 mg/dL, but this was not observed in those participants with lower LDL-C levels. Sex did not appear to modify these associations.

CONCLUSIONS

Adults with both high TG and low HDL-C, particularly those with diabetes, have increased risks of incident CHD and stroke. In particular, those with an LDL-C level ≥130 mg/dL may have an increased risk of incident stroke.

Stroke Risk Factors, Genetics, and Prevention

Stroke is a heterogeneous syndrome, and determining risk factors and treatment depends on the specific pathogenesis of stroke. Risk factors for stroke can be categorized as modifiable and nonmodifiable. Age, sex, and race/ethnicity are nonmodifiable risk factors for both ischemic and hemorrhagic stroke, while hypertension, smoking, diet, and physical inactivity are among some of the more commonly reported modifiable risk factors. More recently described risk factors and triggers of stroke include inflammatory disorders, infection, pollution, and cardiac atrial disorders independent of atrial fibrillation. Single-gene disorders may cause rare, hereditary disorders for which stroke is a primary manifestation. Recent research also suggests that common and rare genetic polymorphisms can influence risk of more common causes of stroke, due to both other risk factors and specific stroke mechanisms, such as atrial fibrillation. Genetic factors, particularly those with environmental interactions, may be more modifiable than previously recognized. Stroke prevention has generally focused on modifiable risk factors. Lifestyle and behavioral modification, such as dietary changes or smoking cessation, not only reduces stroke risk, but also reduces the risk of other cardiovascular diseases. Other prevention strategies include identifying and treating medical conditions, such as hypertension and diabetes, that increase stroke risk. Recent research into risk factors and genetics of stroke has not only identified those at risk for stroke but also identified ways to target at-risk populations for stroke prevention.

Stroke incidence, prevalence and mortality in women worldwide

BACKGROUND

The study of sex differences on stroke incidence, prevalence and mortality is an emerging field of stroke epidemiology and care.

AIMS

This study sought to determine the information available on stroke epidemiology in women worldwide and possible sex differences in stroke epidemiology, and, if so, describe the nature of these differences and whether they are consistent across countries/groups of countries.

SUMMARY

We searched the available literature in English published between 1 January 2008 and 5 May 2015. Out of 17.789 papers only 56 peer-reviewed papers (29 community-based studies, 17 retrospective studies, 6 reviews, and 4 cross-sectional studies) have been included in the study. This review adopted the epidemiologic transition theory, which classifies countries into four stages according to their levels of industrialization and economy. For the first and second stages, reliable registries and health certification are lacking, and therefore our sought after data were very limited.In the third stage, specifically for Eastern Europe (post-socialist countries), the burden from stroke in women was on the rise, while in the fourth stage, despite an aging population, decreases in stroke incidence, prevalence and mortality have been observed, even in subjects older than 80 years for both sexes. However, regarding studies of US populations, these trends for women were less pronounced for African Americans, and Hispanics as well as Indians. This suggests a "gender-gap" regarding access to treatment and care.In conclusion, identifying the presence of differing global burden between the sexes will allow us to better understand how to prevent, treat, and manage both men and women.

Cranial Magnetic Resonance Imaging in Elderly American Indians: Design, Methods, and Implementation of the Cerebrovascular Disease and Its Consequences in American Indians Study

The Cerebrovascular Disease and its Consequences in American Indians (CDCAI) Study recruited surviving members of a 20-year, longitudinal, population-based cohort of American Indians focused on cardiovascular disease, its risk factors, and its consequences. The goal of the CDCAI Study is to characterize the burden, risk factors, and manifestations of vascular brain injury identified on cranial MRI. The CDCAI Study investigators enrolled 1,033 participants aged 60 and older from 11 American Indian communities and tribes in the Northern Plains, Southern Plains, and Southwestern United States. In addition to cranial MRI performed according to standardized protocols, participants underwent extensive medical interview, clinical examination, neurocognitive testing, physical function evaluation, electrocardiogram, and provided blood and urine specimens. Participants also self-administered questionnaires covering demographics, quality of life, and medical history. This report describes the design, implementation, and some of the unique challenges of this study and data collection.

Disparities in Early Transitions to Obesity in Contemporary Multi-Ethnic U.S. Populations

BACKGROUND

Few studies have examined weight transitions in contemporary multi-ethnic populations spanning early childhood through adulthood despite the ability of such research to inform obesity prevention, control, and disparities reduction.

METHODS AND RESULTS

We characterized the ages at which African American, Caucasian, and Mexican American populations transitioned to overweight and obesity using contemporary and nationally representative cross-sectional National Health and Nutrition Examination Survey data (n = 21,220; aged 2-80 years). Age-, sex-, and race/ethnic-specific one-year net transition probabilities between body mass index-classified normal weight, overweight, and obesity were estimated using calibrated and validated Markov-type models that accommodated complex sampling. At age two, the obesity prevalence ranged from 7.3% in Caucasian males to 16.1% in Mexican American males. For all populations, estimated one-year overweight to obesity net transition probabilities peaked at age two and were highest for Mexican American males and African American females, for whom a net 12.3% (95% CI: 7.6%-17.0%) and 11.9% (95% CI: 8.5%-15.3%) of the overweight populations transitioned to obesity by age three, respectively. However, extrapolation to the 2010 U.S. population demonstrated that Mexican American males were the only population for whom net increases in obesity peaked during early childhood; age-specific net increases in obesity were approximately constant through the second decade of life for African Americans and Mexican American females and peaked at age 20 for Caucasians.

CONCLUSIONS

African American and Mexican American populations shoulder elevated rates of many obesity-associated chronic diseases and disparities in early transitions to obesity could further increase these inequalities if left unaddressed.

Causes and Disparities in Death Rates Among Urban American Indian and Alaska Native Populations, 1999-2009

OBJECTIVES

To characterize the leading causes of death for the urban American Indian/Alaska Native (AI/AN) population and compare with urban White and rural AI/AN populations.

METHODS

We linked Indian Health Service patient registration records with the National Death Index to reduce racial misclassification in death certificate data. We calculated age-adjusted urban AI/AN death rates for the period 1999-2009 and compared those with corresponding urban White and rural AI/AN death rates.

RESULTS

The top-5 leading causes of death among urban AI/AN persons were heart disease, cancer, unintentional injury, diabetes, and chronic liver disease and cirrhosis. Compared with urban White persons, urban AI/AN persons experienced significantly higher death rates for all top-5 leading causes. The largest disparities were for diabetes and chronic liver disease and cirrhosis. In general, urban and rural AI/AN persons had the same leading causes of death, although urban AI/AN persons had lower death rates for most conditions.

CONCLUSIONS

Urban AI/AN persons experience significant disparities in death rates compared with their White counterparts. Public health and clinical interventions should target urban AI/AN persons to address behaviors and conditions contributing to health disparities.

Association of hematocrit and pre-hypertension among Chinese adults: the CRC study

Elevated blood pressure is regarded as an independent risk factor for cardiovascular diseases and diabetes. We examined the relation between hematocrit and pre-hypertension as well as the effect of sex, obesity, fasting glucose, and lipids in Chinese adults. The study samples were from a community-based health examination survey in China and included a total of 2,3691 patients with blood pressure in normal range. The odds ratios [ORs, 95 % confidence interval (CI)] of pre-hypertension across increasing quartiles of hematocrit were 1.000, 1.176 (1.050-1.318), 1.213 (1.081-1.363), and 1.364 (1.209-1.540) (P for trend < 0.001), when adjusted for age, sex, body mass index, glutamic-pyruvic transaminase, glutamic-oxalocetie transaminase, serum uric acid, glucose, and lipids. Associations were significant in both men and women, but not in individuals older than 60 years. In addition, low-density lipoprotein cholesterol significantly interacted with hematocrit (P for interaction <0.024). The associations were more evident in patients with low (P < 0.001) and median LDL-C levels (P < 0.013) than those with high glucose levels. Hematocrit was associated with pre-hypertension, and was independent of metabolic risk factors. These associations were not significant in older individuals and low-density lipoprotein cholesterol may modify these associations.

Forced Expiratory Volume in the First Second and Aldosterone as Mediators of Smoking Effect on Stroke in African Americans: The Jackson Heart Study

BACKGROUND

Cigarette smoking is a risk factor for stroke, but the mechanisms by which smoking contributes to stroke are not well understood. This study aimed to evaluate the roles of lung function (represented by forced expiratory volume in the first second (FEV1)) and aldosterone as potential mediators of the association of smoking with stroke.

METHODS AND RESULTS

The data were derived from 5010 Jackson Heart Study participants who had mean follow-up of 97.9 months. Using the Cox proportional hazards model, we estimated the hazard ratios of smoking for total stroke with and without adjustment for FEV1 and/or aldosterone at baseline after controlling for the confounders. The hazard ratio for current smoking (versus never smoking) was 2.70 (95% CI 1.71 to 4.25) for total stroke after adjustment for the confounders. Additional adjustment for FEV1 and aldosterone reduced the hazard ratio to 2.32 (95% CI 1.42 to 3.79), suggesting that 22.4% of the excess risk of current smoking for total stroke is mediated by these factors. FEV1 and aldosterone account for 13.1% and 12.1%, respectively, of the excess risk. The hazard ratio for FEV1 increased (0.61 versus 0.65) after including systemic inflammatory marker C-reactive protein, and the hazard ratios for aldosterone were comparable for the models that included all confounders and smoking status with or without different blood pressure measurements.

CONCLUSIONS

Our findings suggest that the difference in stroke risk between current and never smokers may develop partially through pathways involving lung function and aldosterone and that the mediation effect through aldosterone is independent of blood pressure.