International trends in stroke mortality: 1970-1985

We compared the pattern of cerebrovascular disease (stroke) mortality in men and women aged 40-69 years in 27 countries during 1970-1985 with the decline in coronary heart disease mortality during the same period. Stroke mortality rates declined in 21 and 25 countries for men and women, respectively. In 23 countries the decline in stroke mortality in women was greater than that in men. Countries with the highest rates of stroke mortality are also those with the least favorable secular trend. The rate of decline for stroke mortality is greater than that for coronary heart disease mortality in those countries that experienced a decline in both categories. International comparisons of risk factor levels over time are required to explain the striking differences between countries.     

International trends in mortality from stroke, 1968 to 1994

BACKGROUND AND PURPOSE: The World Health Organization data bank is an invaluable source of information for international comparison of mortality trends. We present rates and trends in mortality from stroke up to 1994, with a particular emphasis on the last 10-year period. Data are presented for men and women in 51 industrialized and developing countries from different parts of the world. METHODS: We included all deaths from cerebrovascular disease for the population aged 35 to 84 years from all the countries in which death certificates were estimated to be available for at least 80% for the period from 1968 to 1994. Age-standardized mortality rates from stroke were calculated for each country for the last available 5 years. Time trends were calculated by using ordinary linear regression and are presented for the entire study period and for 3 separate time periods: 1968 to 1974, 1975 to 1984, and 1985 to 1994. The last 10-year period was further subdivided into 2 parts of 5 years each. We analyzed data separately for men and women and for groups aged 35 to 74 years and 75 to 84 years. RESULTS: The highest rates at the end of the study period for the population aged 35 to 74 years were observed in eastern Europe and previous Soviet Union countries (309 to 156/100 000 per year among men and 222 to 101/100 000 per year among women), Mauritius (268/100 000 per year among men and 138/100 000 per year among women), and Trinidad and Tobago (185/100 000 per year among men and 134/100 000 per year among women). Relatively low to average rates (<100/100 000 per year among men and <70/100 000 per year among women) were reported for Western Europe, with an exception of Portugal (162/100 000 per year among men and 95/100 000 per year among women). The countries with lowest stroke mortality rates at the end of the study period, such as the United States, Canada, Switzerland, France, and Australia, experienced steep declining trends. However, the slope of the decline was substantially reduced during the last 5 years in these countries. Mortality from stroke increased most in the eastern European countries, especially during the last 5 years. Among other high-risk populations, no change in stroke mortality trends was observed in Mauritius, whereas somewhat declining trends were seen in Trinidad and Tobago. CONCLUSIONS: We observed large differences in mortality rates from stroke around the world together with a wide variation in mortality trends. A widening gap was observed between 2 groups of nations, those with low and declining stroke mortality rates and those with high and increasing mortality, in particular, between western and eastern Europe. Eastern European countries should initiate actions aiming at the reduction of stroke risk, perhaps by looking at the examples of Japan and Finland and the other countries that have been the most successful in reducing previously very high mortality from stroke.     

Incidence, mortality, and case-fatality rate of stroke in northern Israel

We studied the incidence and mortality of stroke in northern Israel to determine possible reasons for the differences previously found in mortality from this condition between the sex and ethnic groups in Israel as a whole. We identified 1,149 cases of stroke during 1984. While the age-standardized incidence was higher in men, the case-fatality rate was twice as high in women. After controlling for ethnic origin, we found that incidence was higher only in men of Western origin, while the female rates were higher in women of Asian and North African extraction. The case-fatality rate was substantially higher in women in all ethnic groups. These differences, especially in relation to the case-fatality rate, have important implications for health services in relation to both possible preventive action and to management of the acute disease phase.     

Regional differences in stroke mortality and alcohol consumption in Japan

The relationship between alcohol consumption and stroke mortality in 1975 in 46 prefectures of Japan was investigated. This was done by adjusting salt intake and several socio-economic factors, i.e., the annual per capita income, the number of persons who received public aid, the number of tatamis (a Japanese traditional floor unit) per household, the unemployment rate, and the unmarried or divorce rate, using a stepwise multiple regression analysis. As dependent variables, the sex-specific and age-adjusted mortality for the middle-aged (35-59 years) and for all ages due to stroke were used. For men, alcohol consumption was significantly related to age-adjusted stroke mortalities for the middle-aged and for all ages independent of salt intake and several socio-economic factors. Alcohol consumption was more strongly related to age-adjusted stroke mortality for the middle-aged than for all ages. For women alcohol was weakly correlated with the stroke mortality of the middle-aged. Salt intake was significantly correlated with stroke mortality for women but not for men. Furthermore, the male: female ratios of the age-adjusted stroke mortality for the middle aged and for all ages were analyzed as well, because alcohol is mostly consumed by men in Japan, and it was expected that the sex ratios would be well correlated to alcohol consumption. The results were as expected. Therefore, it was suggested that the regional difference in stroke mortality in Japan may be explained in part by that of alcohol consumption.     

Decline in US stroke mortality. Demographic trends and antihypertensive treatment

Stroke mortality has been falling rapidly in this country since 1973. To investigate age-race-sex effects on stroke mortality, we studied US vital statistics during 1950-1972 and 1973-1981 in 55-64-, 65-74-, and 75-84-year-old race-sex groups. The accelerated rate of decline in stroke mortality since 1973 has had a substantial public health impact, with greater than 200,000 fewer stroke deaths than would otherwise have occurred. For all groups, stroke mortality declined at a greater rate (p less than 0.05) in 1973-1981 than during 1950-1972. The rates of decline during 1973-1981 were greater with increasing age (p less than 0.05) and were more substantial for younger blacks. There were no consistent differences in the rate of decline by sex. The greater rate of decline in absolute stroke mortality in the older age groups and blacks was explained by higher baseline mortality in these groups. Overall, stroke mortality decreased by approximately 2%/yr in 1950-1972 and by approximately 7%/yr after 1973. Rank order of average annual percent decline after 1973 by age-race-sex groups did not correspond to rates of change in treatment or control of hypertension obtained from three national surveys. The accelerated rate of decline after 1973 may have resulted from improved antihypertensive therapy, but our findings fail to confirm this hypothesis and suggest that treatment of hypertension may not be the principal reason for the decline in stroke mortality.     

Secular trends in stroke incidence and mortality. The Framingham Study.

BACKGROUND: The reduction in US stroke mortality has been attributed to declining stroke incidence. However, evidence is accumulating of a trend in declining stroke severity. METHODS: We examined secular trends in stroke incidence, prevalence, and fatality in Framingham Study subjects aged 55-64 years in three successive decades beginning in 1953, 1963, and 1973. RESULTS: No significant decline in overall stroke and transient ischemic attack incidence or prevalence occurred. In women, but not men, incidence of completed ischemic stroke declined significantly. Stroke severity, however, decreased significantly over time. Stroke with severe neurological deficit decreased in later decades, with a fall in rates of severe stroke cases in which patients were unconscious on admission to the hospital. There was no substantial change in the case mix of infarcts and hemorrhages and no decline in hemorrhage to account for the decline in severity. The proportion of isolated transient ischemic attacks increased significantly over the 30 years studied, yielding an apparent and significant decline in case-fatality rates in men only. CONCLUSIONS: Secular trends in stroke incidence and fatality did not follow a clear or definite pattern of decline. While a significant decline in stroke severity occurred over three decades, incidence of infarction fell only in women. The decline in total case fatality rates occurred only in men and resulted largely from an increased incidence of isolated transient ischemic attacks. The severity of completed stroke was significantly lower in the later decades under study.     

Update of trends in mortality from stroke in Italy from 1955 to 1987.

Mortality form stroke in Italy over the period 1955-1987 was analysed in terms of age-specific, age-standardised death certification rates, and by means of a log-linear model to separate the effects of age, cohort of birth and calendar period of death. In males the overall age-adjusted rate on the world standard population fell from 118.4/100,000 population in 1955-1959 to 72.0 in 1985-1987 and in females from 94.8 in 1955-1959 to 54.7 in 1985-1987. The overall decline in age-standardised rates over the 3 decades was thus 39% for males (averaging 1.7%/year) and 42% for females (averaging 1.9%/year). The declines were even greater in truncated rates from 35 to 64 years: from 80.4 to 41.2/100,000 for males (49%), and from 63.0 to 24.1/100,000 for females (62%). Inspection of age-specific rates shows comparable falls--in relative terms--in early and later middle age. For instance, male rates declined from 70.4 to 38.1/100,000 (46%) at age 50-54, and from 1,151.1 to 584.2/100,000 (50%) at age 70-74. Only above age 75 were the falls smaller. In females aged 50-54 years the decline was 63%, and for those aged 70-74 years it was 59%. In young adults, no appreciable changes were observed in either sex. Thus, the age, period and cohort model showed downwards trends in both the period and cohort effect, except for the most recent cohorts on account of an age-cohort interaction. These favourable trends are discussed in relation to better control of hypertension and the potential impact of other risk factors.(ABSTRACT TRUNCATED AT 250 WORDS)     

Predicting mortality in stroke

Physicians are faced with the task of predicting the immediate and long term outcome in stroke patients. It is also important to efficiently and optimally utilize resources. We used APACHE III scoring system or predicting in hospital outcome in patients with stroke. We found it to be sensitive (>90%) and resonably specific (73%) in predicting short term, in-hospital mortality, in our study group.     

Sex differences in stroke

Increasing evidence suggests that sex differences exist in the etiology, presentation, treatment, and outcome from stroke. The reasons for these sex disparities are becoming increasingly explored, but large gaps still exist in our knowledge. Experimental studies over the past several years have demonstrated intrinsic sex differences both in vivo and in animal models which may have relevance to our understanding of stroke in clinical populations. A greater understanding of the differences and similarities between males and females with respect to the risk factors, pathophysiology, and response to stroke will facilitate the design of future clinical trials and enhance the development of treatment strategies to improve stroke care in both sexes. This article reviews the current literature on sex differences in stroke with an emphasis on the clinical data, incorporating an analysis of bench research as it pertains to the bedside.     

Sex differences in stroke

Sex differences in stroke are observed across epidemiologic studies, pathophysiology, treatments, and outcomes. These sex differences have profound implications for effective prevention and treatment and are the focus of this review. Epidemiologic studies reveal a clear age-by-sex interaction in stroke prevalence, incidence, and mortality. While premenopausal women experience fewer strokes than men of comparable age, stroke rates increase among postmenopausal women compared with age-matched men. This postmenopausal phenomenon, in combination with living longer, are reasons for women being older at stroke onset and suffering more severe strokes. Thus, a primary focus of stroke prevention has been based on sex steroid hormone-dependent mechanisms. Sex hormones affect different (patho)physiologic functions of the cerebral circulation. Clarifying the impact of sex hormones on cerebral vasculature using suitable animal models is essential to elucidate male–female differences in stroke pathophysiology and development of sex-specific treatments. Much remains to be learned about sex differences in stroke as anatomic and genetic factors may also contribute, revealing its multifactorial nature. In addition, the aftermath of stroke appears to be more adverse in women than in men, again based on older age at stroke onset, longer prehospital delays, and potentially, differences in treatment.     

Ethnic differences in stroke recurrence

OBJECTIVE: To determine whether stroke recurrence and the effect of recurrence on mortality differ by ethnicity. METHODS: Using methods from the Brain Attack Surveillance in Corpus Christi project, we prospectively identified first-ever ischemic strokes from emergency department logs and hospital admissions (January 2000 to December 2004). Recurrent strokes and deaths were identified for the same period. Cumulative probability of stroke recurrence was estimated. Cox proportional hazards models were used to examine ethnic differences in recurrence and to examine the relation among ethnicity, recurrence, and mortality. RESULTS: During the time interval, 1,345 first-ever ischemic strokes were validated. Median age of patients was 72 years; 53% were Mexican American (MA). There were 126 recurrent strokes. Cumulative risk for recurrence at 30 days and 1 year was 2.6 and 7.5%, respectively. MAs had higher risk for stroke recurrence (risk ratio, 1.57; 95% confidence interval, 1.05-2.34) compared with non-Hispanic white patients, adjusted for demographics, stroke risk factors, and stroke severity. Stroke recurrence was related to mortality to a similar extent across ethnic groups (non-Hispanic white patients: risk ratio, 3.32; 95% confidence interval, 2.07-5.32; MAs: risk ratio, 2.35; 95% confidence interval, 1.42-3.88). INTERPRETATION: MAs had higher stroke recurrence risk compared with non-Hispanic white patients. Stroke recurrence had an important impact on mortality. Efforts to reduce stroke recurrence in MAs are needed.     

World-wide trends in multiple sclerosis mortality

Mortality attributed to multiple sclerosis (MS) was analyzed for 35 countries around the world using World Health Organization reports from 1965 to 1984. Trends were plotted for the United States and Canada, for various regions of Europe, Israel, South America, Asia, Australia and some Pacific countries. In general, MS mortality has declined steadily in North America and most of western Europe as well as in countries with a western culture but has remained stable or increased in eastern and northern Europe. Although several Mediterranean countries reported a recent increased frequency of MS, it was not (yet?) evident in mortality data. Intensive prospective surveillance of MS frequency trends in selected regions of the world will determine the validity of the trends based on mortality.     

Geographic differences in mortality from stroke in North Caroline. 1. Analysis of death certificates.

Analysis of death certification in North Carolina for a three-year period, 1969 through 1971, showed regional differences in mortality rates from stroke in white men, with the highest rates in the Plains (tobacco growing and farming) area and the lowest rates in the Mountain region. These geographic differences in death rates were observed in all but the youngest age decade and also in the various types of stroke, i.e., hemorrhagic and occlusive cerebrovascular diseases. This regional variation in mortality, however, was not present in white women or blacks. The prevalence at death of heart disease, hypertension and diabetes also was higher in the Plains than in the Mountain region, suggesting that the observed geographic variation of stroke mortality is related to one or more of these major risk factors. It is concluded that the geographic differences in stroke mortality, which had been reported during previous decades, are real and are not due to variations in death certification, errors in diagnosis, or other explanations that might artificially produce inaccuracies in vital statistics.