Prevention of primary event. Ischemic stroke risk detection and reduction.

Risk detection and reduction methods for persons at high risk of ischemic stroke involve screening and identification of risk factors. Population-based health surveys affirm a persistent dilemma in the inability to reduce the frequency of ischemic stroke risk factors, such as hypertension, cigarette smoking, obesity, and physical inactivity levels. These alarming trends indicate that "mass approach" policies and programs need to be implemented or rethought to attain maximum levels of benefit in ischemic stroke risk reduction for the entire community.

Fish consumption and the 30-year risk of fatal myocardial infarction.

BACKGROUND: Epidemiologic data on the possible benefit of eating fish to reduce the risk of coronary heart disease have been inconsistent. We used data from the Chicago Western Electric Study to examine the relation between base-line fish consumption and the 30-year risk of death from coronary heart disease. METHODS: The study participants were 1822 men who were 40 to 55 years old and free of cardiovascular disease at base line. Fish consumption, as determined from a detailed dietary history, was stratified (0, 1 to 17, 18 to 34, and > or = 35 g per day). Mortality from coronary heart disease, ascertained from death certificates, was classified as death from myocardial infarction (sudden or nonsudden) or death from other coronary causes. RESULTS: During 47,153 person-years of follow-up, there were 430 deaths from coronary heart disease; 293 were due to myocardial infarctions (196 were sudden, 94 were nonsudden, and 3 were not classifiable). Cox proportional-hazards regression showed that for men who consumed 35 g or more of fish daily as compared with those who consumed none, the relative risks of death from coronary heart disease and from sudden or nonsudden myocardial infarction were 0.62 (95 percent confidence interval, 0.40 to 0.94) and 0.56 (95 percent confidence interval, 0.33 to 0.93), respectively, with a graded relation between the relative risks and the strata of fish consumption (P for trend = 0.04 and 0.02, respectively). These findings were accounted for by the relation of fish consumption to nonsudden death from myocardial infarction (relative risk, 0.33; 95 percent confidence interval, 0.12 to 0.91; P for trend= 0.007). CONCLUSIONS: These data show an inverse association between fish consumption and death from coronary heart disease, especially nonsudden death from myocardial infarction.

Dietary vitamin C, beta-carotene and 30-year risk of stroke: results from the Western Electric Study.

The relations of dietary antioxidants vitamin C and beta-carotene to 30-year risk of stroke incidence and mortality were investigated prospectively in the Chicago Western Electric Study among 1,843 middle-aged men who remained free of cardiovascular disease through their second examination. Stroke mortality was ascertained from death certificates, and nonfatal stroke from records of the Health Care Financing Administration. During 46, 102 person-years of follow-up, 222 strokes occurred; 76 of them were fatal. After adjustment for age, systolic blood pressure, cigarette smoking, body mass index, serum cholesterol, total energy intake, alcohol consumption, and diabetes, relative risks (and 95% confidence intervals) for nonfatal and fatal strokes (n = 222) in highest versus lowest quartiles of dietary beta-carotene and vitamin C intake were 0.84 (0.57-1.24) and 0.71 (0.47-1.05), respectively. Generally similar results were observed for fatal strokes (n = 76). Although there was a modest decrease in risk of stroke with higher intake of beta-carotene and vitamin-C intake, these data do not provide definitive evidence that high intake of antioxidant vitamins decreases risk of stroke.

One-hour postload plasma glucose and risks of fatal coronary heart disease and stroke among nondiabetic men and women: the Chicago Heart Association Detection Project in Industry (CHA) Study.

Associations of baseline one-hour postload plasma glucose with 22-year coronary heart disease, stroke, cardiovascular diseases, and all cause mortality were assessed in five age-specific cohorts of nondiabetic men and women from the Chicago Heart Association Detection Project in Industry: 10,269 men ages 18-39 years; 7993 men ages 40-59 years; 1240 men ages 60-74 years; 6319 women ages 40-59 years; and 932 women ages 60-74 years. Plasma glucose was determined one hour after a 50-gram oral glucose load. Cox regression analyses were used to control for age and other covariates. Generally, higher glucose was significantly associated with mortality from coronary heart disease, stroke, cardiovascular diseases, and all cause mortality in men and women. This large longitudinal study provides evidence that one-hour postload plasma glucose in the absence of clinical diabetes at baseline apparently is an independent risk factor for fatal coronary heart disease and stroke in middle-aged and older nondiabetic men and women, and also for cardiovascular diseases and for all cause mortality.

Fish consumption and stroke in men. 30-year findings of the Chicago Western Electric Study.

BACKGROUND AND PURPOSE: Evidence of a relationship of fish intake to stroke incidence or mortality is weak. This report examines the association of fish consumption with stroke. METHODS: A cohort of 2107 men aged 40 to 55 years from the Chicago Western Electric Study who were free of coronary heart disease and stroke through their first annual reexamination was investigated in relation to baseline fish intake and 30-year risk of fatal and nonfatal stroke. Data on baseline fish intake, categorized into four levels (> or = 35 g/d, 18 to 34 g/d, 1 to 17 g/d, and 0 g/d), were available for 1847 men. Average values of macronutrients and micronutrients from the first two examinations and major coronary and stroke risk factors were assessed in relation to fish consumption. Stroke mortality was ascertained from death certificates and nonfatal stroke from records of the Health Care Financing Administration. RESULTS: During 46,426 person-years of follow-up, 76 stroke deaths occurred. Men consuming > or = 35 g/d of fish (highest level) had a higher age-adjusted death rate from stroke (23.5 per 10,000 person-years) than men in the three other categories of fish consumption. Based on a Cox proportional hazards regression model with adjustment for age, systolic blood pressure, cigarette smoking, serum cholesterol level, diabetes, electrocardiographic abnormalities, and table salt use, hazards ratios (and 95% confidence intervals) for fish consumers compared with nonconsumers were 1.34 (0.53 to 3.41) for > or = 35 g/d, 0.96 (0.41 to 2.21) for 18 to 34 g/d, and 1.00 (0.43 to 2.33) for 1 to 17 g/d. Age-adjusted and multivariate analyses for fatal and nonfatal strokes (n = 222) yielded similar results. CONCLUSIONS: With stroke rates highest in the subgroup reporting highest fish intake, these data do not support the hypothesis of an inverse association of fish consumption with strokes.

Mitral valve prolapse and the risk of stroke after initial cerebral ischemia.

Referral-based studies suggest that patients with cerebral ischemia and mitral valve prolapse are prone to recurrent cerebral ischemic events. Our purpose was to determine the risk of subsequent stroke in a population-based group of patients with ischemic stroke or TIA and mitral valve prolapse. From 1975 through 1990, 49 residents of Olmsted County, MN, had an initial ischemic stroke or TIA and echocardiographically diagnosed mitral valve prolapse. Risk of subsequent stroke in this cohort was compared with the age- and sex-adjusted rates of recurrent stroke after initial cerebral ischemia in the Rochester, MN, population. Mean age of the patients was 72 years. Thirty-one (63%) were women. Nine had subsequent stroke (5.5 per 100 person-years). For Rochester patients who had initial ischemic stroke in the period 1975 through 1984, 10.72 recurrent strokes were expected (relative risk, 0.84; 95% confidence limits, 0.38 to 1.59). For Rochester patients with initial ischemic stroke or TIA in the period 1975 through 1979, 12.31 recurrent strokes were expected (relative risk, 0.73; 95% confidence limits, 0.33 to 1.39). There is no evidence of increased subsequent stroke risk among patients with initial episodes of cerebral ischemia and mitral valve prolapse relative to the age- and sex-adjusted recurrent stroke rates in the community.

Risk of stroke with mitral valve prolapse in population-based cohort study.

BACKGROUND AND PURPOSE: The purpose of this study was to clarify whether mitral valve prolapse increases the subsequent risk of stroke. METHODS: A historical cohort study was conducted on 1079 residents of Olmsted County, Minnesota, who had an initial echocardiographic diagnosis of mitral valve prolapse between 1975 and 1989 without prior stroke or transient ischemic attack and who were followed up for first stroke occurrence. RESULTS: There was an overall twofold increase in the incidence of stroke among individuals with mitral valve prolapse relative to the reference population (standardized morbidity ratio, 2.1; 95% confidence interval, 1.3 to 3.2). Sex, duration of follow-up from the diagnosis of mitral valve prolapse, or calendar year of initial diagnosis did not modify the association. Within the cohort of patients who were at least 35 years old at diagnosis of mitral valve prolapse, a time-dependent proportional-hazards multivariate model and a person-years analysis revealed that age, ischemic heart disease, congestive heart failure, and diabetes mellitus were important determinants for stroke when person-years of observation after mitral valve replacement were excluded. Among seven persons with mitral valve replacement, three strokes occurred in 24 person-years of follow-up. For those with an auscultatory diagnosis of mitral valve prolapse only as the indication for echocardiography (44%), the risk of stroke relative to the population was 1.0 (95% confidence interval, 0.2 to 2.9); for those with another cardiac diagnosis, the standardized morbidity ratio was 2.5 (95% confidence interval, 1.5 to 4.0). CONCLUSIONS: Individuals with uncomplicated mitral valve prolapse did not have an increased risk of stroke, although a small increase in the risk may not have been detected.

A population-based study of stroke in the setting of mitral valve prolapse: risk factors and infarct subtype classification.

OBJECTIVE: To determine the frequency of risk factors and the mechanisms of stroke in patients with cerebral infarction and echocardiographically diagnosed mitral valve prolapse in the general population. DESIGN: We conducted a population-based study in Olmsted County, Minnesota, which encompassed the period from 1975 through 1989. MATERIAL AND METHODS: Study subjects were identified by using the Rochester Epidemiology Project medical records-linkage system. Cardiac and neurologic data were summarized, and a two-sided chi 2 test or Fisher's exact test was used for statistical analysis. RESULTS: Among residents of Olmsted County, Minnesota, 33 had echocardiographically diagnosed mitral valve prolapse and a first cerebral infarction between 1975 and 1989. The mean patient age was 71 years, and more than half (52%) were men. Risk factors for stroke included hypertension (55%), smoking (42%), coronary artery disease (27%), atrial fibrillation or flutter (24%), congestive heart failure (21%), hypertensive heart disease (21%), prior myocardial infarction (12%), diabetes (9%), and sick sinus syndrome (3%). Cerebral infarction subtypes were as follows: cardioembolic source (excluding mitral valve prolapse only), 30%; lacuna, 12%; large-vessel atherosclerosis, 9%; other, 6%; and infarction of uncertain cause (including mitral valve prolapse), 42%. CONCLUSION: Most Olmsted County patients with cerebral infarction and echocardiographically diagnosed mitral valve prolapse had other risk factors for stroke, and most had identifiable mechanisms of infarction other than embolism due to mitral valve prolapse.

Outcome and pathogenesis of stroke is conditioned by place of stroke occurrence.

To investigate whether stroke pathogenesis and sequelae are conditional on place of initial stroke occurrence, 2,238 incident stroke cases among Rochester, Minnesota, residents in the period from 1950 to 1984 were evaluated. Virtually compete case ascertainment of first strokes in Rochester nursing homes (153 strokes), hospitals (194), and homes (1,891) was possible through a medical record linkage system. Stroke cases were reviewed by a neurologist applying uniform criteria. Although most patients had the first stroke at home (84%), there was an increasing trend over the study period of first strokes occurring while patients were hospitalized. For nursing home incident strokes, there was a linear increase over calendar time of patients being hospitalized. This paralleled an overall increase in patients being hospitalized for the first stroke. Persons with initial stroke in the home who were hospitalized had lower 5-year observed survival than those who were not hospitalized (p 0.0067), an indication that those with more severe stroke were more likely to be hospitalized. The 5-year relative survival was highest for initial stroke occurrence in the home (57%), intermediate for in-hospital strokes (35%), and lowest for nursing home strokes (11%). Comorbid conditions undoubtedly contributed to the difference in survival patterns. A cardiac source of embolus was present in more than 40% of strokes occurring in the nursing home and in over half the strokes that occurred in the hospital.

Population-Based in-hospital stroke morbidity and mortality.

To investigate the risk and prognostic factors for in-hospital incident stroke and stroke mortality, surveillance was conducted on Rochester, MN, residents free of stroke when admitted to the hospital in the years 1950 through 1984. The in-hospital first stroke attack rates remained stable for the calendar years 1970,1976, and 1980. Of the first strokes that occurred in the hospital, 42% were adventitious. In approximately 60% of patients with adventitious strokes, the strokes developed within 2 days after a hospital procedure. Patients with cardiovascular problems were the majority among the patients who had nonadventitious strokes. Four independently significant prognostic factors associated with stroke 30-day mortality included age (relative risk, 1.6 per 10 years), calendar year (relative risk, 0.7 per 10 years), atrial fibrillation or flutter (relative risk, 2.3), and intracranial hemorrhage compared with cerebral infarction (relative risk, 12.4). These findings emphasize the heterogeneity of the pathophysiologic mechanisms for in-hospital stroke.