Increased treatment of hypertension does not explain the decline in stroke mortality in the United States, 1970-1980

Analysis of cerebrovascular disease mortality trends in Andalusia (1980-2014)

INTRODUCTION

In recent decades, mortality rates for cerebrovascular diseases (CVD) have decreased significantly in many countries. This study analyses recent tendencies in CVD mortality rates in Andalusia (1980-2014) to identify any changes in previously observed sex and age trends.

PATIENTS AND METHODS

CVD mortality and population data were obtained from Spain's National Statistics Institute database. We calculated age-specific and age-standardised mortality rates using the direct method (European standard population). Joinpoint regression analysis was used to estimate the annual percentage change in rates and identify significant changes in mortality trends. We also estimated rate ratios between Andalusia and Spain.

RESULTS

Standardised rates for both males and females showed 3 periods in joinpoint regression analysis: an initial period of significant decline (1980-1997), a period of rate stabilisation (1997-2003), and another period of significant decline (2003-2014).

CONCLUSIONS

Between 1997 and 2003, age-standardised rates stabilised in Andalusia but continued to decrease in Spain as a whole. This increased in the gap between CVD mortality rates in Andalusia and Spain for both sexes and most age groups.

Thirty-Year Trends in Mortality from Cerebrovascular Diseases in Korea

Background and Objectives

Cerebrovascular disease is a leading cause of mortality and morbidity in Korea. Understanding of cerebrovascular disease mortality trends is important to reduce the health burden from cerebrovascular diseases. We examined the changing pattern of mortality related to cerebrovascular disease in Korea over 30 years from 1983 to 2012.

Subjects and Methods

Numbers of deaths from cerebrovascular disease, hemorrhagic stroke, and cerebral infarction were obtained from the national Cause of Death Statistics. Crude and age-adjusted mortality rates were calculated for men and women for each year. Penalized B-spline methods, which reduce bias and variability in curve fitting, were used to identify the trends of 30-year mortality and identify the year of highest mortality.

Results

During the 30 years, cerebrovascular disease mortality has markedly declined. The age-adjusted cerebrovascular disease mortality rate has decreased by 78% in men and by 68% in women. In the case of hemorrhagic stroke, crude mortality peaked in 2001 but age-adjusted mortality peaked in 1994. Between 1994 and 2012, age-adjusted mortality from hemorrhagic stroke has decreased by 68% in men and 59% in women. In the case of cerebral infarction, crude and age-adjusted mortality rates steeply increased until 2004 and 2003, respectively, and both rates decreased rapidly thereafter.

Conclusion

Cerebrovascular disease mortality rate has significantly decreased over the last 30 years in Korea, but remains a health burden. The prevalence of major cardiovascular risk factors are still highly prevalent in Korea.

Long-term trends in cardiovascular disease mortality and association with respiratory disease

The recent decline in cardiovascular disease mortality in Western countries has been linked with changes in life style and treatment. This study considers periods of decline before effective medical interventions or knowledge about risk factors. Trends in annual age-standardized death rates from cerebrovascular disease, heart disease and circulatory disease, and all cardiovascular disease are reviewed for three phases, 1881–1916, 1920–1939, and 1940–2000. There was a consistent decline in the cerebrovascular disease death rate between 1891 and 2000, apart from brief increases after the two world wars. The heart disease and circulatory disease death rate was declining between 1891 and 1910 before cigarette smoking became prevalent. The early peak in cardiovascular mortality in 1891 coincided with an influenza pandemic and a peak in the death rate from bronchitis, pneumonia and influenza. There is also correspondence between short-term fluctuations in the death rates from these respiratory diseases and cardiovascular disease. This evidence of ecological association is consistent with the findings of many studies that seasonal influenza can trigger acute myocardial infarction and episodes of respiratory infection are followed by increased risk of cardiovascular events. Vaccination studies could provide more definitive evidence of the role in cardiovascular disease and mortality of influenza, other viruses, and common bacterial agents of respiratory infection.

Where will the next generation of stroke treatments come from?

Remarkable progress has occurred over the last two decades in stroke interventions. Many have been developed on the basis of their efficacy in other disorders. This "inheritance" approach should continue, but two areas where completely novel therapeutic targets might emerge are the stimulation of neuroplasticity and unraveling the genetic code of stroke heterogeneity (Table 2). For the former, the next steps are to identify small-molecule, nontoxic compounds that most effectively enhance plasticity in animal models, and then subject them to clinical trial in humans. For the latter, more and larger-scale cooperative GWASs in carefully phenotyped stroke populations are required to better understand the polygenic nature of cerebrovascular disease. Then, the physiological relevance of genetic abnormalities can be determined in in vitro and in vivo systems before candidate compounds are developed.

Increases in Antihypertensive Prescriptions and Reductions in Cardiovascular Events in Canada

The Canadian Hypertension Education Program, an extensive professional education program to improve the management of hypertension, was started in 1999. There were very large increases in diagnosis and treatment of hypertension in the first 4 years after initiation of the program. The purpose of this study was to examine the association between the changes in antihypertensive therapy with changes in hospitalization and death from major hypertension-related cardiovascular diseases in Canada between 1992 and 2003. Using various national databases, Canadian standardized yearly mortality and hospitalization rates per 1000 for stroke, heart failure, and acute myocardial infarction were calculated for individuals aged ≥20 years and regressed against antihypertensive prescription rates. Changes in rates were examined in a time series analysis. There were significant reductions ( P <0.0001) in the rate of death from stroke, heart failure, and myocardial infarction starting in 1999. There was also a reduction in hospitalization rate from stroke ( P <0.0001) and heart failure ( P <0.0001) but not myocardial infarction in 1999. The changes in death ( P <0.001 for all 3 diseases) and hospitalization ( P <0.0001 for stroke and heart failure; P =0.018 for acute myocardial infarction) were associated with the increases in antihypertensive prescriptions. This study demonstrates that the reduction in cardiovascular death and hospitalization rates is associated with an increase in antihypertensive prescriptions and that it coincides with the introduction of the Canadian Hypertension Education Program. The Canadian Hypertension Education Program educational model for improving health care could be adopted by other countries with well-developed professional and scientific societies.

Child-to-adult body mass index and height trajectories: a comparison of 2 British birth cohorts

Markers of growth and changes of body mass index (BMI) are associated with adult chronic disease risk. To better understand such associations, the authors examined the 1946 (n approximately 5,300) and 1958 (n approximately 17,000) British birth cohorts to establish how child-to-adult height and BMI have changed across generations. Individuals born in 1958 were no heavier at birth than those born in 1946, but they were taller in childhood by about 1 cm on average, grew faster thereafter, and were 3-4 cm taller by adolescence. The 1958 cohort achieved adult height earlier and were taller by 1 cm, an increase that was entirely due to their longer leg length. BMI trajectories diverged from early adulthood, with a faster rate of BMI gain in the 1958 cohort than in the 1946 cohort, although the mean BMI at 7 years and rate of childhood gain had not shown an increase. By midadulthood, the 1958 cohort had on average a greater BMI (1-2 kg/m(2)), larger waist (6-7 cm) and hip (5 cm) circumferences, and a higher prevalence of obesity (25.1% vs. 10.8% in males and 23.7% vs. 14.8% in females). Changes in height and adiposity over a relatively short period of 12 years suggest the likelihood of opposing trends of influences on later disease risk in these populations.

Stroke

Stroke is the second most common cause of death and major cause of disability worldwide. Because of the ageing population, the burden will increase greatly during the next 20 years, especially in developing countries. Advances have occurred in the prevention and treatment of stroke during the past decade. For patients with acute stroke, management in a stroke care unit, intravenous tissue plasminogen activator within 3 h or aspirin within 48 h of stroke onset, and decompressive surgery for supratentorial malignant hemispheric cerebral infarction are interventions of proven benefit; several other interventions are being assessed. Proven secondary prevention strategies are warfarin for patients with atrial fibrillation, endarterectomy for symptomatic carotid stenosis, antiplatelet agents, and cholesterol reduction. The most important intervention is the management of patients in stroke care units because these provide a framework within which further study might be undertaken. These advances have exposed a worldwide shortage of stroke health-care workers, especially in developing countries.

Trends in Ethnic Disparities in Stroke Incidence in Auckland, New Zealand, During 1981 to 2003

Background and Purpose— Although geographical variations in stroke rates are well documented, limited data exist on temporal trends in ethnic-specific stroke incidence.

Methods— We assessed trends in ethnic-specific stroke rates using standard diagnostic criteria and community-wide surveillance procedures in Auckland, New Zealand (NZ) in 1981 to 1982, 1991 to 1992, and 2002 to 2003. Indirect and direct methods were used to adjust first-ever (incident) and total (attack) rates for changes in the structure of the population and reported with 95% CIs. Ethnicity was self-defined and categorized as “NZ/European,” “Maori,” “Pacific peoples,” and “Asian and other.”

Results— Stroke attack (19%; 95% CI, 11% to 26%) and incidence rates (19%; 95% CI, 12% to 24%) declined significantly in NZ/Europeans from 1981 to 1982 to 2002 to 2003. These rates remained high or increased in other ethnic groups, particularly for Pacific peoples in whom stroke attack rates increased by 66% (95% CI; 11% to 225%) over the periods. Some favorable downward trends in vascular risk factors, such as cigarette smoking, were counterbalanced by increasing age, body mass index, and diabetes in certain ethnic groups.

Conclusions— Divergent trends in ethnic-specific stroke incidence and attack rates, and of associated risk factors, have occurred in Auckland over recent decades. The findings provide mixed views as to the future burden of stroke in populations undergoing similar lifestyle and structural changes.

Trends in Stroke Incidence in Auckland, New Zealand, During 1981 to 2003

BACKGROUND AND PURPOSE

Long-term trends in stroke incidence in different populations have not been well characterized, largely as a result of the complexities associated with population-based stroke surveillance.

METHODS

We assessed temporal trends in stroke incidence using standard diagnostic criteria and community-wide surveillance procedures in the population (approximately 1 million) of Auckland, New Zealand, over 12-month calendar periods in 1981-1982, 1991-1992, and 2002-2003. Age-adjusted first-ever (incident) and total (attack) rates, and temporal trends, were reported with 95% confidence intervals (CIs). Rates were analyzed by sex and major age groups.

RESULTS

From 1981 to 1982, stroke rates were stable in 1991-1992 and then declined in 2002-2003, to produce overall modest declines in standardized incidence (11%; 95% CI, 1 to 19%) and attack rates (9%; 95% CI, 0 to 16%) between the first and last study periods. Some favorable downward trends in vascular risk factors such as cigarette smoking were counterbalanced by increasing age and body mass index, and frequency of diabetes, in patients with stroke.

CONCLUSIONS

There has been a modest decline in stroke incidence in Auckland over the last 2 decades, mainly during 1991 to 2003, in association with divergent trends in major risk factors.

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.

Trends in validated cases of fatal and nonfatal stroke, stroke classification, and risk factors in southeastern New England, 1980 to 1991 : data from the Pawtucket Heart Health Program

BACKGROUND AND PURPOSE

Recent US data suggest there is a slowing of the decline in stroke mortality rates, accompanied by a constant morbidity rate. Hospital discharge rates for patients with stroke are influenced by numerous factors, and community-based surveillance data for validated cases are rare. Thus, reasons for the observed trends remain unclear. In the present study, we examined trends in validated cases of stroke for 1980 to 1991 in the combined populations of the Pawtucket Heart Health Program study communities and examined concomitant trends in classification, use of diagnostic procedures, and levels of risk factors.

METHODS

Discharges for residents aged 35 to 74 years with International Classification of Diseases, Ninth Revision codes 431, 432, and 434 to 437 were identified through retrospective surveillance. A physician reviewed the medical records to validate case status.

RESULTS

Between 1980 and 1991, 2269 discharges were confirmed as representing definite or probable strokes (59.5% of 3811 cases reviewed). The fatal stroke rate declined (P<0.005) and the nonfatal stroke rate remained constant in both sexes. Case-fatality rates declined significantly (P=0.003), and among strokes, the relative odds of death in 1990 versus 1980 was 0.50 (95% CI 0.34 to 0.72). The proportion of stroke discharges in which the patient received a CT scan or MRI increased 120%, and fewer strokes were classified as ill defined. Hypertension prevalence, treatment, and control rates remained constant in these populations.

CONCLUSIONS

Although causes for the observed trends remain unclear, results suggest that the decline in mortality rates is due to improved survival rates for patients with stroke. However, constant morbidity rates combined with constant rates of hypertension highlight the need for improved prevention to reduce the impact of stroke.

Time trends in long-term survival after stroke: the Northern Sweden Multinational Monitoring of Trends and Determinants in Cardiovascular Disease (MONICA) study, 1985-1994

BACKGROUND AND PURPOSE

Stroke mortality rates and case fatality of stroke have declined since the beginning of the 1970s in Sweden, but the incidence of stroke has been stable. The aim of this study was to analyze trends in long-term survival after stroke.

METHODS

Within the framework of the population-based WHO Multinational Monitoring of Trends and Determinants in Cardiovascular Disease (MONICA) Project, all acute stroke events were recorded in the age group 25 to 74 years in northern Sweden during the period 1985 to 1994. All first-ever stroke patients were followed for information on vital status (minimum follow-up time was 1 year). Survival time was related to time period of stroke onset, stroke diagnosis, and concomitant diseases.

RESULTS

Survival times for a total of 6819 first-ever stroke patients (4057 men and 2762 women) were analyzed. Age-adjusted odds ratio for death within 1 year after stroke was 0.70 (95% confidence interval [CI], 0.55 to 0.88) in the period 1993 to 1994 as compared with the period 1985 to 1986 in men and 0.69 (95% CI, 0.53 to 0.90) in women. Corresponding odds ratios were 0.73 in men and 0.70 in women among those who survived the first 28 days. Similar improvements were seen for 3- and 5-year survival. Improvements in survival over time were most marked among patients with ischemic stroke. There was no improvement in survival over time among patients with the most severe deficits at onset.

CONCLUSIONS

Gradually improved survival, both short and long term, was observed during the 10-year study period. The improvements are not explained by changes in known confounding prognostic factors.

Opposing national stroke mortality trends in Poland and for African Americans and whites in the United States, 1968 to 1994

BACKGROUND AND PURPOSE

The United States (US) has experienced declines in stroke mortality in contrast to the increases reported for Poland. As part of the Poland and US Agreement on Cardiovascular and Cardiopulmonary Research, stroke mortality trends in Polish and US subpopulations were compared in the context of cross-population differences in competing causes of death and determinants of stroke.

METHODS

Age-adjusted annual stroke, cardiovascular disease (CVD), non-CVD, and all-cause mortality rates were determined for men and women aged 35 to 64 and 65 to 74 years from 1968 to 1994 for African Americans and US whites and in Poland. Mean annual percent changes of mortality rates were estimated during 1968 to 1980 and 1981 to 1994 with the use of piecewise log-linear regression.

RESULTS

US stroke mortality rates declined 3.7% to 4.8% annually during 1968 to 1980 and 2.0% to 3.1% during 1981 to 1994, with similar declines in each ethnic, gender, and age group. Polish rates increased 3.3% to 5.5% annually for all age-gender groups in Poland during 1968 to 1980. Polish men aged 35 to 64 experienced increasing rates during 1981 to 1994 (1.6% annually), while Polish women and older men experienced slight declines or little change. Only Polish men aged 35 to 64 years exhibited increases in stroke, CVD, and non-CVD mortality rates during both time intervals.

CONCLUSIONS

Poland and the US experienced opposing stroke mortality rate trends between 1968 and 1994. These national and ethnic trends occurring in just one generation suggest major effects of lifestyle, socioenvironmental, and/or medical care determinants.

Increasing hospital admission rates for intracerebral hemorrhage during the last decade

BACKGROUND

The incidence and mortality of all types of strokes, including intracerebral hemorrhages, declined during the 1970s. However, some evidence exists that these trends stabilized or reversed during the 1980s. In the present study, a large North American population was observed from 1981 to 1989 to assess changes in the annual hospital admission rates of intracerebral hemorrhage.

METHOD

Data provided by the Connecticut Health Information Management and Exchange (CHIME, Wallingford, Connecticut), a state-wide clinical database of records submitted voluntarily by all of Connecticut's 36 acute care, nongovernment hospitals, was analyzed for all patients with primary diagnosis of intracerebral hemorrhage (ICD-9-CM=431) for the fiscal years 1981, 1983, 1985, 1987, 1988, and 1989.

RESULTS

During the time periods studied, there were 3,277 hospitalizations with a primary diagnosis of intracerebral hemorrhage. There was an initial annual hospital admission rate of 12 per 100,000 in 1981. Rates steadily increased to nearly 20 per 10,000 in 1988 and 1989. This increase in hospital admission rates from intracerebral hemorrhage was statistically significant when the data were adjusted for gender, race, and age (P<.001). When admission rates for intracerebral hemorrhage were stratified by age, admission rates increased dramatically only in those 65 years and older (P<.001). The in-hospital death rate decreased during the study decade (P=.004); however, age-adjusted analysis indicated that in-hospital deaths increased significantly (P<.001) in patients 65 years and older.

CONCLUSIONS

Hospital admission rates for intracerebral hemorrhage nearly doubled from 1981 to 1989. This change may be due to an actual increase in the annual incidence of intracerebral hemorrhage caused by mechanisms that are not yet fully understood.

Stroke in a defined elderly population, 1967-1985. A less lethal and disabling but no less common disease

BACKGROUND AND PURPOSE

Decline in stroke mortality in recent decades has been well documented in the United States and other countries. This study, based on a well-defined population with comprehensive medical records available for research purposes, seeks to explain decline in stroke mortality among older persons between 1967 and 1985. The study specifically explores the competing explanatory mechanisms of decreased incidence of stroke versus decreased case-fatality rate.

METHODS

We conducted a retrospective analysis of three successive period cohorts (1967 through 1971, 1974 through 1978, and 1981 through 1985) of persons > or = 65 years of age enrolled in a large group model HMO in a metropolitan community. All new hospitalized and a sample of nonhospitalized strokes were ascertained, and samples of first-ever strokes were studied. Incidence, case-fatality rates, survival times, and comorbidities were compared across cohorts.

RESULTS

There was no significant change in stroke incidence over time; however, 1-month case fatality declined dramatically from 33% in 1967 through 1971 to 18% in 1981 through 1985 (P < .01); median survival increased from 213 to 1092 days. Indices of reduced severity included declines in coma from 27% to 12% (P < .01) and in wheelchair- or bed-bound status from 40% to 30% (P = .067). Cases with and without CT scan in 1981 to 1985, when this procedure became widely available in the health plan, were similar in severity, thereby reducing the possibility of ascertainment bias.

CONCLUSIONS

In this well-defined older population, stroke has become a less lethal and disabling though no less common disease. This finding fails to support the "compression of morbidity" hypothesis while supporting a model of delayed progression for stroke in this age group.

Ten-year trends in stroke incidence and mortality in the FINMONICA Stroke Study

BACKGROUND AND PURPOSE

The trends in stroke incidence reported so far have not been entirely consistent, although declining trends in mortality from stroke have been reported from a number of studies around the world. This study aims to evaluate the 10-year trends (from 1983 through 1992) in incidence, attack rate, and mortality of stroke in the Finnish population.

METHODS

A population-based stroke register was set up in the early 1980s to collect data on all suspected events of acute stroke that occurred in the population aged 25 to 74 years permanently residing in three geographic areas of Finland: the provinces of Kuopio and North Karelia in eastern Finland and the Turku-Loimaa area in southwestern Finland. Trends in age-standardized attack rates, incidence, and mortality were calculated for the period studied.

RESULTS

During the 10-year study period, 11 392 acute stroke events occurred in the monitored populations. A statistically significant decline was observed in the pooled FINMONICA data, both in the incidence of stroke (-1.7% with 95% confidence interval [CI], -3.0% to -0.5% per year in men; -2.2% with 95% CI, -3.6% to -0.7% per year in women) and in mortality from stroke (-5.2% with 95% CI, -8.2% to -2.2% per year; -4.7% with 95% CI, -8.2% to -1.2% per year). The attack rate of stroke also declined significantly in both sexes. When the areas were considered separately, the declining trends were observed within each area. The decline in incidence of stroke was, however, statistically significant only among men and women in Kuopio and among women in Turku/Loimaa. Mortality declined significantly in all three areas among men but among women only in Kuopio. The incidence to mortality rate ratio increased during the study period, indicating a steeper fall in mortality than in incidence.

CONCLUSIONS

A substantial decline in both stroke incidence and mortality was observed in the adult and elderly population in the FINMONICA study areas. Part but not all of the decline in stroke mortality, observed also in the official mortality statistics, can be attributed to the decline in stroke incidence during this 10-year period.

Epidemiology of hypertension in African American women

To describe the epidemiology of hypertension in U.S. African American women and to highlight priority areas for future research, data from the nationwide surveys of the U.S. National Center for Health Statistics, from selected multicenter studies of the U.S. National Heart, Lung, and Blood Institute, as well as from selected other population-based studies, were reviewed. In 1988 through 1991, an estimated 3 million African American women aged 18 and older had hypertension. Compared with that in U.S. whites, hypertension in black women is characterized by higher incidence, earlier onset, longer duration, higher prevalence, and higher rates of hypertension-related mortality and morbidity. Risk factors for hypertension incidence in black women include obesity and weight gain. The effectiveness of drug therapy of hypertension has been established in black women, and important gains in rates of treatment and control have been accomplished. Nevertheless, rates of hypertension-related mortality for black women remain among the highest in the industrialized nations. Further research on causes and prevention of hypertension in black women is needed. Goals related to prevention and control of hypertension in African Americans for the year 2000 have been established and must be vigorously pursued.

Stroke in China, 1986 through 1990

BACKGROUND AND PURPOSE

Incidence of stroke varies markedly in different world populations. In seven Chinese cities, the effect of a program of risk factor modification on the incidence and mortality of stroke was studied and compared with a control population. This article describes the incidence of stroke in the control populations for the years 1986 through 1990.

METHODS

Incidence (first-ever strokes only) for 1986 was obtained by door-to-door interview with heads of households with subsequent verification on examination by a neurologist and review of medical and/or hospital records. In subsequent years, cases were ascertained with a three-tier monitoring system: by community health workers, local medical centers, and the Beijing Neurosurgical Institute.

RESULTS

Average annual age-adjusted incidence per 100,000 was 215.6 (261.5 for males, 174.5 for females; P < .001). There was a significant drop in the total number of cases from 137 in 1986 to 106 in 1990, but the age-adjusted rate showed a significant drop for males only (322.3 to 182.5, P < .001). Marked differences in average annual age-adjusted rates existed among the seven cities, from 486.4 for Harbin to 80.9 for Shanghai. This difference in rate among cities was found for both sexes but was more pronounced in males.

CONCLUSIONS

The stroke incidence rates in China, like those in Japan, are among the higher ones in the world. In recent years, there has been an apparent decline in stroke incidence. Marked differences in rates were found between males and females with decline in incidence occurring almost exclusively in males. There were also marked differences in stroke incidence among the cities studied. These differences may result in part from differences in diet, alcohol and cigarette consumption, or prevalence of hypertension.

Changes in the sex ratio of stroke mortality in the period of 1955 through 1990

BACKGROUND AND PURPOSE

Stroke mortality worldwide has decreased in men and women in most industrialized countries, except in eastern European countries. The purpose of this study was to compare the sex ratio of stroke mortality between populations and over time. This approach may help to determine the factors influencing this ratio.

METHODS

The sex ratios (men to women) of stroke mortality between ages 55 to 64, 65 to 74, and 75 to 84 years from 27 populations between 1955 and the latest available year were analyzed using World Health Organization data. The relationship between log stroke mortality and age and the relationships between alcohol, animal fat, cigarette consumption, and urinary cation excretion and the sex ratio of stroke mortality were also analyzed.

RESULTS

The mean sex ratio of stroke mortality increased 50%, 34%, and 15% in the three age classes, respectively, over 35 years. Highly significant relationships of log stroke mortality with age exist, which vary between men and women and among countries. In general, stroke mortality changed in the same direction in both sexes but decreased earlier and more rapidly in women than in men. Alcohol consumption and urinary sodium excretion correlated positively and significantly with the sex ratio. The time trends of the sex ratio also correlated positively and significantly with the time trends of cigarette consumption. No relationship with animal fat consumption was found.

CONCLUSIONS

The sex ratio of stroke mortality is increasing with time and decreasing with age. Differences in lifestyle among countries and over the last three decades may contribute partially to these differences in sex ratio.

Dietary sodium, potassium, saturated fat, alcohol, and stroke mortality

BACKGROUND AND PURPOSE

Although positive relationships between blood pressure, dietary sodium, and stroke risk have been reported, studies on the relationship between dietary sodium and stroke mortality are scarce. A significant relationship between dietary saturated fatty acids (SFA) and stroke risk has not been reported in epidemiological studies. The purpose of this study was to examine the relationship between dietary sodium and SFA together with dietary potassium, alcohol, and stroke risk.

METHODS

The sex- and age-specific stroke mortality rates (log-transformed) for the age classes 45 to 54, 55 to 64, and 65 to 74 years for the period between 1986 and 1988 were obtained from World Health Organization statistics. The 24-hour urinary excretion levels of sodium (U-Na) and of potassium (U-K), dietary SFA intake levels, and alcohol consumption levels were obtained from dietary surveys performed in 17 countries. The relationships between stroke mortality and the dietary variables were examined by Pearson correlation and multiple regression analysis.

RESULTS

The highest degree of correlation, both in Pearson correlation and multiple regression analysis, was found between U-Na and log-stroke mortality (P < .01 to P < .001). In multiple regression analysis, U-Na (P < .01 to P < .001), SFA (P < .05 to P < .01), and alcohol (P < .05) independently, significantly, and positively correlated with log-stroke mortality rates, and U-K correlated negatively (P < .05). The exceptions were SFA in both sexes in the age class 45 to 54 years, alcohol in both sexes in the age class 45 to 54 years and in women in the age class 55 to 64 years, and U-K in women in the age class 65 to 74 years.

CONCLUSIONS

These results suggest that dietary factors, especially sodium and SFA, are of primary importance as determinants of stroke mortality at the population level.

Improved survival of stroke patients during the 1980s. The Minnesota Stroke Survey

BACKGROUND AND PURPOSE

The underlying reasons for the decline in stroke mortality in the United States are not well understood and have been the subject of ongoing debate. This study was undertaken to determine whether survival of hospitalized stroke patients has changed during the 1980s, thereby contributing to the decline in stroke mortality during that period.

METHODS

For the years 1980, 1985, and 1990, we obtained listings of discharge diagnoses from hospitals in the Minneapolis-St Paul metropolitan area and identified all hospitalizations with a discharge diagnosis code of acute cerebrovascular disease according to the International Classification of Diseases, 9th Revision. A 50% random sample of men and women aged 30 to 74 years was selected in each survey for detailed medical record abstraction. Standardized sets of criteria for stroke were then used to validate acute stroke events throughout the 1980s. Each of the three period cohorts of hospitalized stroke patients (1980, 1985, and 1990) was followed for at least 2 years for all-cause mortality end point.

RESULTS

A total of 1853 patients met minimal criteria for acute stroke: 564 patients in 1980, 598 patients in 1985, and 691 patients in 1990. Controlling for age, the odds of death within 2 years after stroke were approximately 40% lower in 1990 than in 1980. The relative odds of 2-year death in 1990 (versus 1980) were 0.65 (95% confidence interval, 0.47 to 0.89) and 0.60 (95% confidence interval, 0.42 to 0.85) for men and women, respectively. The improved survival was evident in the short term (28 days) as well as for stroke patients who survived that period. Analysis according to stroke subtype revealed that improved survival of ischemic stroke and specifically of stroke with no apparent cardioembolic source largely accounted for the overall trend. The prognosis of stroke patients who were admitted in a comatose state has not changed during that decade.

CONCLUSIONS

Despite the absence of any clear major advances in acute stroke therapy, survival of stroke patients substantially improved during the 1980s. The underlying reasons for this unexpected yet remarkable trend remain uncertain but may include improved supportive and rehabilitative care of stroke victims as well as a change in the natural history of the disease.

Trends in incidence, case-fatality rate, and severity of stroke in northern Sweden, 1985-1991

BACKGROUND AND PURPOSE--Incidence, case-fatality rate at 28 days, and severity of acute stroke were recorded for 7 years in a large population-based stroke register to understand the reasons for the decline in stroke mortality in northern Sweden.

METHODS

Within the framework of the World Health Organization MONICA Project, acute stroke was monitored in people aged 35 to 74 years in northern Sweden from 1985 through 1991 (target population in 1985, 238,948).

RESULTS

The annual incidence of stroke decreased by an average of 2.3%/y in men aged 35 to 64 years (P = .074) and increased significantly by 1.1%/y in men aged 65 to 74 years (P = .041). No significant changes in incidence occurred in either age group in women. The 28-day case-fatality rate in first-ever strokes (both sexes together) declined from 21.9% to 15.4% in patients aged 65 to 74 years (P = .02). Among survivors, the proportion with extensive motor deficits (at any time during the first 28 days) declined in patients younger than 65 years as well as in those older than 65 years (P = .007 and P = .019, respectively). In patients aged 35 to 64 years, the proportion with aphasia/dysphasia also decreased significantly (P = .032), but no such trend was seen in those aged 65 to 74 years.

CONCLUSIONS

A shift toward higher ages has been noted in the occurrence of first-ever strokes in men, while incidence has remained unchanged in women. During the 7 years of observation, stroke has become a less severe disease.

Defining the impact of prevention and improved management upon stroke mortality

Stroke mortality in developed countries has significantly declined. The purpose of this study is to demonstrate a cross-sectional model of aging and mortality with which the impact of prevention and improved management upon stroke mortality can be quantified. Stroke mortality in the U.S. between 1951 and 1988 among whites aged 20-85 years was analyzed using the Strehler-Mildvan modification of the Gompertz relationship between aging and mortality. Between 1951 and 1988, environmental (non-genetic) influences upon U.S. stroke mortality declined 16.4% among white men and 22.16% among white women. Cross-sectional mortality analysis may be necessary to eliminate the effect of differential survival bias inherent in cohort mortality analysis.

Stroke incidence and case fatality in Australasia. A comparison of the Auckland and Perth population-based stroke registers

BACKGROUND AND PURPOSE

Population-based studies are crucial for identifying explanations for the decline in mortality from stroke and for generating strategies for public health policy. However, the present particular methodological difficulties, and comparability between them is generally poor. In this article we compare the incidence and case fatality of stroke as assessed by two independent well-designed incidence studies.

METHODS

Two registers of acute cerebrovascular events were compiled in the geographically defined metropolitan areas of Auckland, New Zealand (population 945,369), during 1991-1992 for 12 months and Perth, Australia (population 138,708), during 1989-1990 for 18 months. The protocols for each register included prospective ascertainment of cases using multiple overlapping sources and the application of standardized definitions and criteria for stroke and case fatality.

RESULTS

In Auckland, 1803 events occurred in 1761 residents, 73% of which were first-ever strokes. The corresponding figures for Perth were 536 events in 492 residents, 69% of which were first-ever strokes. Both studies identified a substantial proportion of nonfatal strokes managed solely outside the hospital system: 28% in Auckland and 22% in Perth of all patients registered. The age-standardized annual incidence of stroke (all events) was 27% higher among men in Perth compared with Auckland (odds ratio, 1.27; P = .016); women tended to have higher rates in Auckland, although these differences were not statistically significant. In both centers approximately a quarter of all patients died within the first month after a stroke. There were significant differences in the prevalence of hypertension among first-ever strokes.

CONCLUSIONS

These two studies emphasize the importance of identifying all patients with stroke, both hospitalized and nonhospitalized, in order to measure the incidence of stroke accurately. The incidence and case fatality of stroke were remarkably similar in Auckland and Perth in the early 1990s. However, there are differences in the sex-specific rates that correspond to differences in the pattern of risk factors.

Trends in survival of hospitalized stroke patients between 1970 and 1985. The Minnesota Heart Survey

BACKGROUND AND PURPOSE

Age-adjusted stroke mortality rates declined approximately 50% between 1970 and 1990 in both the United States and Minnesota, but the reasons for this decline are not clear. This report examines possible improvements in short- and long-term survival of hospitalized definite stroke patients in the Minneapolis-St Paul (the Twin Cities) metropolitan area during this period.

METHODS

Fifty percent random samples of patients discharged with an acute stroke diagnosis from area hospitals were selected in 1970 (n = 1200), 1980 (n = 1040), and 1985 (n = 896). Trained nurses abstracted pertinent clinical data from the hospital charts. By standardized clinical criteria similar to World Health Organization criteria (without computed tomography data), 376, 442, and 453 definite strokes were established for 1970, 1980, and 1985, respectively.

RESULTS

Age- and sex-adjusted 28-day case fatality of definite stroke improved significantly from 1970 to 1985; the odds ratio (OR) of death within 28 days in 1985 (versus 1970) patients was 0.55 (95% confidence interval [CI], [0.39, 0.77]). Substantial improvements in 28-day mortality were observed both from 1970 to 1980 and from 1980 to 1985, although the latter change was not statistically significant. Further adjustment for predictors of early stroke mortality (such as level of consciousness) somewhat attenuated these results. Age- and sex-adjusted 5-year survival of definite stroke also improved significantly from 1970 to 1985 (OR, 0.72; 95% CI, [0.54, 0.96]), although the improvement was restricted to the 1970 to 1980 time period (OR, 0.76; 95% CI, [0.57, 1.01]). None of the survival trends differed significantly between men and women.

CONCLUSIONS

There were marked improvements in survival from 1970 to 1985 among hospitalized stroke patients in the Twin Cities. These improvements occurred almost exclusively in the acute hospitalization phase. Although the advent of computed tomography and improvements in hospital record-keeping during this period prevent an unequivocal conclusion, improved medical care and decreased severity of stroke probably contributed to gains in survival.

Trends in stroke mortality and incidence in Finland in the 1970s and 1980s

This article presents trends in stroke mortality and incidence in Finland among people aged 25 to 74 years. Between 1971 and 1980, stroke mortality declined steeply: 4.1% per year among men and 5.5% per year among women. Between 1981 and 1991 the decline was smaller; about 2.2% per year in men and 2.8% per year in women. The North Karelia stroke register showed that stroke mortality declined in men from 155 per 100,000 per year in 1972 to 1973, to 87 per 100,000 per year in 1982 to 1983, and in women from 114 to 44 per 100,000 per year. A slight decline in mortality was observed during the 1980s in men, but not in women. The incidence of stroke also declined in North Karelia during the 1970s, from 328 to 248 per 100,000 per year in men, and from 230 to 141 per 100,000 in women. In the FINMONICA stroke register, the average rate of decline in incidence of stroke between 1983 and 1989 was 1.7% per year in men and 1.8% per year in women. Declines in incidence and mortality from subarachnoid hemorrhage were observed in both men and women; nevertheless it was the decline in cerebral infarction that accounted for most of the changes since about 80% of all strokes are cerebral infarctions. In conclusion, despite steep falls in stroke mortality and incidence in the 1970s, stroke mortality is still high in Finland compared with other nations. During the 1980s, the decline in stroke mortality was less and incidence leveled off until it resumed from 1987 to 1989.(ABSTRACT TRUNCATED AT 250 WORDS)

Stroke trends in Australia and New Zealand: mortality, morbidity, and risk factors

Stroke death rates are declining in Australia and New Zealand as in many other industrialized countries. An explanation for the decline in mortality requires information from population-based incidence studies. Two studies that meet the criteria for well-designed stroke studies have been conducted, one in Auckland, New Zealand, in 1991 and the other in Perth, Western Australia, in 1988 to 1989. Comparisons between the two studies reveal similar incidence and case-fatality rates for both men and women, reflecting the similar mortality rates. The Auckland study repeats one carried out 10 years earlier and allows an insight into the changes in incidence, case fatality, and severity of stroke in a large urban population. Between the two study periods there was no overall change in the incidence rates but case-fatality rates improved in both men and women. Although there have been significant improvements in the level of smoking in both Australia and New Zealand during the 1980s, only marginal improvements in mean population blood pressure have occurred, despite efforts and resources directed at identification of individuals with raised blood pressure. This high-risk strategy has apparently had only a very limited impact on reducing the incidence of stroke in the population.

Decline in US stroke mortality in the era before antihypertensive therapy

BACKGROUND AND PURPOSE

This study was done to determine if reported declines in stroke mortality in the era before antihypertensive therapy are artifactual.

METHODS

This study involved analyses of national and state vital statistics data using adjusted and specific rates.

RESULTS

Adoption of the third revision of the International List of Causes of Death in 1921 produced an abrupt 6.6% decrease in stroke mortality rates, but otherwise, changes in disease classification systems had little effect on stroke mortality rates. Adoption of the second revision of the joint-cause manual produced a 9.2% drop in stroke death rates, but other revisions of the joint-cause selection rules had little effect. While rates for the expanding group of states in the death registration area progressively declined, rates for fixed component areas remained constant until around 1925 and then declined. Reselection of the underlying cause from aggregate multiple cause data for 1917, 1925, and 1940 using uniform selection rules confirmed a decline after 1925. Correlation analyses of rates of change for stroke and heart disease rates did not support a shift in diagnosis to explain the divergent trends.

CONCLUSIONS

The apparent decline in stroke mortality rates before 1925 is an artifact of changes in disease classification systems, joint-cause selection rules, and nonrandom incorporation of states with different mortality rates into the expanding registration area. The decline after 1925 could not be explained by changes in coding systems or joint-cause selection rules or by a shift in diagnosis from stroke to heart disease.

The decline in stroke mortality. An epidemiologic perspective

The evidence that treatment of hypertension prevents stroke is incontrovertible. Several observations, however, suggest that improvements in the prevalence of antihypertensive treatment cannot explain all of the recent decline in stroke mortality. Changes in nutritional patterns may explain some of the observed decline. Prospective studies have demonstrated conclusively an independent, increasing risk of hemorrhagic, but not thrombotic, stroke at higher levels of alcohol use. Stroke mortality is associated inversely with fat and protein intake. Dietary sodium has been linked to stroke in ecologic studies but not in prospective studies. Ecologic studies have suggested that foods high in vitamin C and potassium protect against stroke; an inverse association of potassium intake with fatal stroke has been demonstrated in cohort studies. Two studies in humans also suggest a protective effect of serum selenium against subsequent stroke. Determination of the influence of nutrients on stroke incidence offers tantalizing opportunities for future research and possibly, intervention.

Stroke mortality and case-fatality rates in three geographic areas of Finland from 1983 to 1986

BACKGROUND AND PURPOSE

Our aim was to describe the mortality and early case-fatality rates of stroke in three geographic areas of Finland during 1983 to 1986 by means of a community-based stroke register and to estimate the accuracy of registration of stroke deaths in the official statistics compared with the FINMONICA stroke register.

METHODS

Annual and average mortality and case-fatality rates of stroke were derived from data collected in the FINMONICA stroke register during 1983 to 1986. Age-specific and age-standardized rates were calculated for the three areas, and the results were compared with the official mortality statistics and with the case-fatality figures published previously in the literature for Finland and elsewhere.

RESULTS

Mortality from stroke in the three FINMONICA areas was between 73 and 90 per 100,000 per year among men aged 25 to 74 years and between 42 and 55 per 100,000 per year among women in the same age group. Average case-fatality was similar in the three areas and globally high: 20% to 27% in men and 24% to 28% in women. Approximately half of the fatal strokes occurred within less than 2 days from the onset of the attack, and a further 25% within the first week. Hemorrhagic strokes accounted for 54% to 81% of all fatal strokes occurring in less than 2 days among men, while among women the corresponding proportions varied in the three areas between 35% and 74%. Of cerebral infarctions, approximately 28% to 37% among men and 19% to 20% among women were fatal within less than 2 days. Although the number of fatal strokes was similar in both the FINMONICA register and official mortality statistics, only 82% to 85% of the stroke cases were common in both registers; a further 13% to 14% of the cases classified as stroke deaths in the FINMONICA register could also be found in the official mortality statistics, but the underlying cause of death was something other than stroke.

CONCLUSIONS

The reliability of the Finnish official mortality statistics with regard to stroke deaths is reasonably good in aggregate numbers, but at the individual level considerable discrepancies seem to occur. Mortality from stroke in Finland has not declined further after 1979 and remains high internationally. Early case-fatality of stroke also seems higher in Finland than in most other countries. We believe that both the high incidence of stroke and the severity of the attacks are contributing to mortality and case-fatality rates of stroke in Finland.

Stroke prophylaxis: hypertension management and antithrombotic therapy

OBJECTIVE

To review trials involving risk factor management and pharmacologic therapy for the prevention of stroke.

DATA SOURCES

English-language literature published between 1966 and 1992 was analyzed; pertinent literature is reviewed.

STUDY SELECTION

Studies that evaluated the impact of risk factor management on prevention of vascular events were selected. In addition, trials assessing the safety and efficacy of pharmacologic intervention in primary and secondary stroke prevention were evaluated.

DATA EXTRACTION

Trials were evaluated for their ability to demonstrate a decrease in stroke occurrence.

DATA SYNTHESIS

Various trials were analyzed in several categories. Studies evaluating risk factor management of hypertension and cardiogenic cerebral emboli were reviewed and recommendations made based on a consensus of these trials. The use of antiplatelet agents in stroke prevention was addressed by a review of pertinent trials and meta-analyses.

CONCLUSIONS

The control of risk factors and the use of antiplatelet agents significantly reduces the risk of vascular events. Benefit from different therapies may be specific to certain patient populations and recommendations are made for these patients.

Antihypertensive treatment and US trends in stroke mortality, 1962 to 1980

OBJECTIVES

This study examines the association between increases in antihypertensive pharmacotherapy and declines in stroke mortality among 96 US groups stratified by race, sex, age, metropolitan status, and region from 1962 to 1980.

METHODS

Data on the prevalence of controlled hypertension and socioeconomic profiles were obtained from three successive national health surveys. Stroke mortality rates were calculated using data from the National Center for Health Statistics and the Bureau of the Census. The association between controlled hypertension trends and stroke mortality declines was assessed with weighted regression.

RESULTS

Prior to 1972, there was no association between trends in controlled hypertension and stroke mortality declines (beta = 0.04, P = .69). After 1972, groups with larger increases in controlled hypertension experienced slower rates of decline in stroke mortality (beta = 0.16, P = .003). Faster rates of decline were modestly but consistently related to improvements in socioeconomic indicators only for the post-1972 period.

CONCLUSIONS

These results do not support the hypothesis that increased antihypertensive pharmacotherapy has been the primary determinant of recent declines in stroke mortality. Additional studies should address the association between declining stroke mortality and trends in socioeconomic resources, dietary patterns, and cigarette smoking.

The US decline in stroke mortality: what does ecological analysis tell us?

We review a study in this issue that concludes, from analyses of ecological associations, that the use of medication to lower high blood pressure has caused at most a small decline in US stroke mortality rates. Our analysis suggests that other possible sources of the decline may be population-wide falls in levels of blood pressure, cigarette smoking, and coronary heart disease mortality, as well as improved treatment of cardiac and respiratory sequelae of stroke. Although the ecological method is powerful for answering questions about medical interventions' population-wide effects on disease, it must be used with care. Of particular concern are variables with meanings that differ between the ecological and the individual levels, the number of ecological units available for analysis, the sample size within the ecological units, and the range of independent variables used in ecological regression.

New insights and approaches to reduce end-organ damage in the treatment of hypertension: subsets of hypertension approach

Antihypertensive therapy should be directed toward reduction of all end-organ damage including congestive heart failure, left ventricular hypertrophy, coronary heart disease, myocardial infarction, cerebrovascular accident, and chronic renal failure. The Subsets of hypertension approach is based on pathophysiology, hemodynamics, risk factor reduction for end-organ damage, concomitant diseases and problems, demographics, adverse effects on quality of life, compliance, and total health care costs. This approach provides a more individualized and logical treatment of the hypertensive syndrome and addresses the metabolic and structural abnormalities that are present.

Hypertension, cigarette smoking, and the decline in stroke incidence in eastern Finland

Finland has high rates of both cardiovascular disease and cardiovascular disease risk factors. We studied random samples of the population 30-59 years of age for risk factors in two provinces of eastern Finland in 1972 and 1977. We then followed both cohorts until 1985 through linkage with national hospital discharge and death certificate registers. The prevalence of hypertension and smoking in both provinces declined between 1972 and 1977, as did the stroke incidence in the 8-year period of follow-up of each cohort. We observed no differences in stroke incidence between the two provinces. The relative risk of stroke in the later period (1977-1985) was 0.71 and 0.58 for men and women, respectively, when compared with the earlier period (1972-1980). Overall, 28% of all stroke events could be attributed to hypertension, 17% to smoking, and 43% to these two factors jointly. The decrease in the prevalence of hypertension and smoking accounted for about 29% of the decline.

Slowdown in the decline of stroke mortality in the United States, 1978-1986

The gradual decline in stroke mortality rates observed in the United States since 1900 accelerated markedly around 1973 for whites and around 1968 for blacks. During the next decade stroke mortality rates decreased by almost 50% so that the United States now experiences one of the lowest stroke mortality rates in the world. Beginning in 1979, however the annual rate of decline in stroke mortality began to slow considerably. Comparing the period 1979-1986 with the previous decade, a 57% slowing in the absolute rate of decline (as estimated by the slope of the linear portion of the mortality curve) was observed for white men; the corresponding slowdowns in the rate of decline were 58% for white women, 44% for black men, and 62% for black women. If the decline during the 1980s had continued at the rate observed for the period 1968/73-1978, there would have been 131,000 fewer stroke deaths during the period 1979-1986, 28,000 fewer in 1986 alone. This slowdown in the rate of decline in stroke mortality is occurring while mortality rates for both coronary heart disease and all causes are leveling off. The reasons for this change in the mortality trend remain unknown, and corresponding trends in the treatment and control of hypertension do not provide an entirely satisfactory explanation.

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.