Decreasing trend in incidence and mortality from stroke in Hisayama residents, Japan

History of cardiovascular epidemiology in Japan

There are several patterns of epidemiological study in Japan. One is the international collaborative studies, such as Seven Countries Study, NI-HON-SAN Study, International Study of Salt and Blood Pressure (INTERSALT), International Study of Macro-and Micro-nutrients and Blood Pressure (INTERMAP), and Monitoring of Cardiovascular Disease (MONICA). The next one is the several cohort studies in Japanese unique surveys, such as Hisayama Study, Osaka-Akita Study, Tanno-Sobetsu Study, Suita Study, Ohazama Study, National Integrated Project for Prospective Observation of Noncommunicable Disease and Its Trends in the Aged (NIPPON DATA), Japan Collaborative Cohort (JACC), and Japan Public Health Center-Based Study (JPHC). Finally, some recent special meta-analysis in Japan are Japan Arteriosclerosis Longitudinal Study (JALS) and Evidence for Cardio-vascular Prevention from Observational Cohorts in Japan (EPOCH-JAPAN). The aim of this review is to introduce the history of epidemiologcal study, especially, cardiovascular epidemiology from the mid-20th century to in the early 21st century by dividing three patterns.

Characteristics, risk factors and mortality of stroke patients in Kyoto, Japan

OBJECTIVES

The aim of the study was to evaluate the characteristics, risk factors and outcome of recent stroke patients in Kyoto, Japan.

DESIGN

We analysed stroke patients in the registry with regard to their characteristics, risk factors and mortality. Cox proportional hazards regressions were used to calculate adjusted HRs for death.

SETTINGS

The Kyoto prefecture of Japan has established a registry to enrol new stroke patients in cooperation with the Kyoto Medical Association and its affiliated hospitals

PARTICIPANTS

The registry now has data on 14 268 patients enrolled from 1 January 1999 to 31 December 2009. Of these, 12 774(89.5%) underwent CT, 9232 (64.7%) MRI, 2504 (17.5%) angiography and 342 (2.4%) scintigraphy. Excluding 480 (3.3%) unclassified patients, 13 788 (96.6%) patients formed the basis of further analyses which were divided into three subtypes: cerebral infarction (CI), cerebral haemorrhage (CH) and subarachnoid haemorrhage (SAH).

RESULTS

A total of 13 788 confirmed stroke patients in the study cohort comprised 9011 (86.3%) CI, 3549 (25.7%) CH and 1197 (8.7%) SAH cases. The mean age ±SD was 73.3±11.8, 69.1±13.6 and 62.7±13.5 in the CI, CH and SAH cases, respectively. Men were predominant in the CI and CH cases, whereas women were predominant in the SAH cases. The frequencies of risk factors were different among the subtypes. Mortality was worst in SAH, followed by CH, and least in CI. HRs for death adjusted for age, sex, histories of hypertension, arrhythmia, diabetes mellitus and hyperlipaemia and use of tobacco and/or alcohol showed a significant (p<0.001) difference among CI (as reference), CH (3.71; 3.11 to 4.43) and SAH (8.94; 7.21 to 11.11).

CONCLUSIONS

The characteristics, risk factors and mortality were evaluated in a quantitative manner in a large Japanese study cohort to shed light on the present status of stroke medicine.

Epidemiology and registry studies of stroke in Japan

Stroke is the most prevalent cardiovascular disease in Japan. This review introduces two epidemiologic studies and four registry studies of stroke in Japan. The Hisayama Study was begun as a population-based prospective cohort study of cerebrovascular and cardiovascular diseases in 1961 in the town of Hisayama. Most of the deceased subjects of the study underwent autopsy examinations from the beginning of the study. Changes in stroke trends in the last 50 years were clarified by comparison of data from different study cohorts registered every 13 to 14 years. The Suita Study was based on a random sampling of Japanese urban residents. Several reports from this study showed the significance of pre-hypertension, as well as hypertension, as a risk factor for stroke by itself and in combination with other underlying characteristics. In addition, the Japan Multicenter Stroke Investigators' Collaboration (J-MUSIC), the Japan Standard Stroke Registry Study, the Fukuoka Stroke Registry, and the Stroke Acute Management with Urgent Risk-factor Assessment and Improvement (SAMURAI) rt-PA Registry are explained as registry studies involving Japanese stroke patients.

Cost-effectiveness and budget impact analyses of a long-term hypertension detection and control program for stroke prevention

OBJECTIVES

The nation-wide, community-based intensive hypertension detection and control program, as well as universal health insurance coverage, may well be contributing factors for helping Japan rank near the top among countries with the longest life expectancy. We sought to examine the cost-effectiveness of such a community-based intervention program, as no evidence has been available for this issue.

METHODS

The hypertension detection and control program was initiated in 1963 in full intervention and minimal intervention communities in Akita, Japan. We performed comparative cost-effectiveness and budget-impact analyses for the period 1964-1987 of the costs of public health services and treatment of patients with hypertension and stroke on the one hand, and incidence of stroke on the other in the full intervention and minimal intervention communities.

RESULTS

The program provided in the full intervention community was found to be cost saving 13 years after the beginning of program in addition to the fact of effectiveness that; the prevalence and incidence of stroke were consistently lower in the full intervention community than in the minimal intervention community throughout the same period. The incremental cost was minus 28,358 yen per capita over 24 years.

CONCLUSION

The community-based intensive hypertension detection and control program was found to be both effective and cost saving. The national government's policy to support this program may have contributed in part to the substantial decline in stroke incidence and mortality, which was largely responsible for the increase in Japanese life expectancy.

Trends in the incidence of stroke and cardiovascular risk factors on the isolated island of Okinawa: the Miyakojima study

BACKGROUND

Rapid deterioration of cardiovascular risk control, especially obesity, has occurred in Okinawa; this may affect cardiovascular disease incidence, including stroke.

METHODS

Cross-sectional field studies were conducted in 2 periods, 1988-1991 as the first period, and 2002-2005 as the second period, in the isolated island of Okinawa, Miyakojima. To evaluate population backgrounds related to cardiovascular risk factors, data from the health checkup programs conducted in 1987 and 2001 were surveyed.

RESULTS

Total of 257 patients in the first period and 370 in the second were diagnosed with first-time stroke. The age-adjusted annual incidence rate of first-time stroke of the first and second periods was 124 and 144 per 100,000 standard population of Japan. The age-adjusted annual incidence rate showed an upward trend for brain infarction (50 to 73) and downward trend for brain hemorrhage (61 to 54); however, those trends were not significant. The health checkup surveys illustrated that blood pressure decreased in all age groups during the second survey period. However, the body mass index increased in patients aged 50 years or more. Fasting blood glucose levels of patients aged 30-79 years and non-HDL cholesterol levels of patients aged 50-79 years significantly increased.

CONCLUSIONS

In Miyakojima, the incidence of first-time stroke and all of its subtypes did not change significantly between two periods, even though blood pressure decreased significantly in the second period. Metabolic deterioration may be associated with the upward trend in incidence of brain infarction.

Trend of Stroke Incidence in a Japanese Population: Takashima Stroke Registry, 1990-2001

Background

In Japan, stroke mortality and incidence started to decline during the 1960s. The recent unfavourably diverging trends in risk factors make it uncertain whether the decline will continue. Few comprehensive stroke registries of long research duration exist in Japan to illustrate the trends in stroke incidence.

Objective

We examined 12-year stroke registration data to evaluate the current trend in a Japanese population.

Methods

Data were obtained from the Takashima Stroke Registry, covering approximately 55000 residents of Takashima County in central Japan. We calculated the age-adjusted stroke incidence rates (/100 000 person-years) and 95% confidence intervals for 1990–1992, 1993–1995, 1996–1998, and 1999–2001. We applied the direct method to adjust for the age distribution among the four periods. The incidence time trend was determined by calculating the average annual change across the study years using negative binomial regression analysis.

Results

There were 1453 (men: 771 and women: 682) registered first-ever stroke cases during 1990–2001. The diagnosis was established by neuro-imaging in 93·6% of the cases. The average age was 69·4 years in men and 74·2 years in women. The age-adjusted incidence rates of stroke across the four observation periods were 143·1 (confidence interval: 127·4-158·8) in 1990–1992, 147·4 (confidence interval: 131·9–162·8) in 1993–1995, 120·4 (confidence interval: 106·7–134·0) in 1996–1998, and 122·9 (confidence interval: 109·6–136·2) in 1999–2001. The stroke incidence across the study years showed an insignificant time trend, with an average annual change of −0·33% (confidence interval: −2·44 to 1·78) per year. Similar trends were observed for both men and women and stroke subtypes.

Conclusions

The previously reported declining trend in stroke incidence may have levelled off or slowed down considerably in the Japanese population.

Determinants of long-term mortality after stroke

Risk factors of death for a population of 409 patients with well-defined cerebrovascular disease (patients with subarachnoidal hemorrhage excluded) admitted to the Stroke Unit were studied with the aid of the life table technique, log rank test, and multivariate analysis with BMDP's program for regression on the survival curves with Cox's proportional hazard model. The estimated proportion of survivors was 77% after three months, 69% after one year, and 32% after five years. Patients with intracerebral hemorrhage and embolic cerebral infarction had the worst outcome. Impaired consciousness on admission was the most important risk factor of death followed by high age, previous cardiac failure, diabetes mellitus and male sex.

Explanation for the Japanese paradox: prevention of increase in coronary heart disease and reduction in stroke

Japan's age-adjusted rate for mortality from stroke increased after the Second World War until 1965 and then showed a significant decline until 1990; however, the age-adjusted rate for mortality from all heart disease and coronary heart disease (CHD) increased until 1970 and then declined slowly. A puzzling question is why the rate of mortality from CHD declined in spite of an increase in serum total cholesterol level following an increase in fat consumption. It was confirmed that CHD incidence was far lower in several Japanese populations compared to Western countries in the " Monitoring Trends and Determinants in Cardiovascular Disease " (MONICA) project; therefore, the lower CHD mortality in Japan stems from the lower CHD incidence. CHD risk factors based on epidemiologic cohort studies in Japan were no different from those of other industrialized countries: hypertension, hypercholesterolemia, smoking and diabetes mellitus (DM). So, how can we explain this phenomenon?There are three possible explanations. One is the decline in population blood pressure level and the prevalence of hypertension during the years 1965-1990; the second is the decline in smoking rate in men and women; the third is that the serum total cholesterol level for middle-aged and elderly populations remains 5-15 mg/dL lower than that of the US elderly counterpart, although men aged 40-49 in Japan and the US had similar serum total cholesterol levels. It was also noted that elderly people in Japan, as observed in the Seven Countries Study, had far lower serum total cholesterol levels in midlife, i.e., around 160 mg/dL in the 1960s. This was not the case for elderly in the US where a higher serum total cholesterol level was observed in midlife. In conclusion, the lower serum cholesterol level in the past of Japanese middle-aged and elderly people compared to Western counterparts helps to maintain the low CHD incidence and mortality supported by the declining trend in blood pressure level and smoking rate for both men and women.

Secular trends in the incidence, mortality, and survival rate of gastric cancer in a general Japanese population: the Hisayama study

To examine secular trends in the incidence and mortality of gastric cancer in a Japanese community, Hisayama, we established three study-cohorts of Hisayama residents aged > or =40 years in 1961 (1637 subjects), 1974 (2054), and 1988 (2602). Each cohort was followed up for ten years. The age-standardized mortality from gastric cancer significantly decreased from 2.4 per 1000 person-years in the first cohort to 0.8 in the third cohort for men, and from 1.0 to 0.2, respectively, for women (p < 0.01 for trend in both sexes). The five-year survival rate after gastric cancer significantly improved from the first (32.6%) to the third cohort (73.0%, p < 0.01) for men and from 43.2% to 72.3% (p < 0.05), respectively, for women. The age-standardized incidence of cancer in men was not different among the cohorts (4.3 per 1000 person-years in the first, 5.0 in the second, and 4.9 in the third cohort), while it decreased significantly in women (2.0, 1.8, and 1.2, respectively, p < 0.01 for trend). In conclusion, our findings suggest that in a Japanese population, the mortality from gastric cancer declined during the past 40 years, due mainly to the improvement of survival in both sexes and a decrease in the incidence for women.

Trends in Five-Year Survival and Risk of Recurrent Stroke after First-Ever Stroke in the Perth Community Stroke Study

BACKGROUND

Few studies provide information on trends in the long-term outcome of stroke. We aimed to determine trends in survival and recurrent stroke, over 5 years after first-ever stroke, for 2 cohorts of patients enrolled in the Perth Community Stroke Study in 1989-90 and 1995-96.

METHODS

For 12-month periods beginning February 1989 and February 1995, all individuals with an acute stroke who were resident in a geographically-defined and representative region of Perth, Western Australia, were registered and followed-up prospectively 5 years after the index event.

RESULTS

The 5-year cumulative risk of death was 59% (95% confidence interval (CI) 53%, 65%) and 58% (95% CI 52%, 65%) for the 1989-90 and 1995-96 cohorts, respectively (p = 0.94). The 5-year cumulative risk of first recurrent stroke was 32% (95% CI 25%, 40%) and 23% (95% CI 16%, 30%) for the 1989-90 and 1995-96 cohorts, respectively (p = 0.07).

CONCLUSIONS

Although no statistically significant improvement occurred in 5-year survival after first-ever stroke in Perth between 1989-90 and 1995-96, there was a statistically nonsignificant trend towards a smaller cumulative risk of recurrent stroke over 5 years after a first-ever stroke. Serial community-based studies of the incidence and outcome of stroke are an important means of monitoring the translation of proven preventive interventions to improvements in population health.

Specific alcoholic beverage and blood pressure in a middle-aged Japanese population: the High-risk and Population Strategy for Occupational Health Promotion (HIPOP-OHP) Study

The purpose of this study was to clarify the effects of popular Japanese alcoholic beverages on blood pressure. We performed a cross-sectional study on 4335 Japanese male workers using baseline data from an intervention study. We defined six groups according to the type of alcoholic beverage that provided two-thirds of the subject's total alcohol consumption: beer, sake (rice wine), shochu (traditional Japanese spirits), whiskey, wine and others. The partial regression coefficients of daily alcohol intake (1 drink=11.5 g of ethanol) to systolic blood pressure (SBP) and diastolic blood pressure (DBP) were 0.87(P<0.001, standard error (s.e.)=0.09) and 0.77(P<0.001, s.e.=0.06), respectively. A comparison among the types of alcoholic beverages mainly consumed revealed significant differences in SBP and DBP. Both SBP and DBP were highest in the shochu group. However, an analysis of covariance adjusting for total alcohol consumption resulted in the disappearance of these differences. Although after adjustment for total alcohol consumption, the shochu group exhibited a significant positive association with 'high-normal blood pressure or greater' (odds ratio 1.43, 95% confidence interval 1.06-1.95) compared with the beer group, this significant relation disappeared after adjusting for the body mass index (BMI), urinary sodium and potassium excretion. The pressor effect, per se, of popular Japanese alcoholic beverages on blood pressure may not be different among the types of alcoholic beverages after adjusting for other lifestyle factors.

Association of the mitochondrial DNA 16189 T to C variant with lacunar cerebral infarction: evidence from a hospital-based case-control study

A transition of T to C at nucleotide position 16189 in the hypervariable D-loop region of mitochondrial DNA (mtDNA) has attracted research interest for its probable correlation with increasing insulin resistance and development of diabetes mellitus (DM) in adult life. In this article, we present our observations of the positive relationship between this variant and cerebral infarction. Six hundred and one subjects in two groups-one with cerebral infarction (307 cases), the other with no cerebral infarction (294 cases)-were recruited. Their clinical features, fasting blood sugar and insulin levels, and insulin resistance index, were recorded. Patients with cerebral infarction were further categorized into four different subgroups according to the TOAST criteria for stroke classification. The results showed the occurrence of the mtDNA 16189 variant in 34.2% of patients with cerebral infarction and in 26.5% of normal controls. The difference in the occurrence rates between the two groups was statistically significant (P = 0.041). Further studies of the occurrence rate in each stroke subgroup revealed that the variant occurred at the highest frequency in the small vessel subgroup (41.5%). The difference in occurrence rate between this subgroup and the normal controls is highly significant (P = 0.006). These results correlated well with the findings of significantly increased levels of average fasting blood insulin and a higher index of average insulin resistance in the small vessel subgroup of patients harboring this mtDNA variant. Taken together, we suggest that the mtDNA 16189 variant is a predisposing genetic factor for the development of insulin resistance and may be related to various phenotypic expressions in adult life such as development of DM and vascular pathologies involved in stroke and cardiovascular diseases.

Risk estimation for hypertension based on follow-up health examination data in a small village in Kumamoto prefecture, Japan

The estimation of risk for incidence of hypertension was carried out by follow-up study in a small village in Kumamoto Prefecture, Japan (N=750, 48.2±15.2months). The most significant risk in both sexes was blood pressure at entry. As for other risks, age, total cholesterol, and BMI in females were significant risks for systolic and diastolic blood pressure changes to greater than the borderline level. These factors in males were not significant. From the results of analysis using Cox's proportional hazards model, drinking in males was shown to be a significant risk for diastolic change, and in females for systolic change. It was concluded that excessive drinking in both sexes and obesity in females led to important health problems associated with hypertension among the subjects of the study.

Decreasing incidence of stroke in central Finland, 1985-1993

INTRODUCTION

During the last decades the age-standardized stroke mortality has declined in Finland as in many other industrialized countries. Epidemiological studies have, however, not been consistent in explaining this fall in mortality. Our aim was to shed light on this question by using two consecutive, population-based surveys.

PATIENTS & METHODS

The target of the two one-year surveys was the population living in the Jyväskylä Region of central Finland, and the surveys were performed in 1985-86 (population 114,669) and 1993 (population 123,547). The case finding methods and the diagnostic criteria were identical in both studies. All hospital records and autopsy reports of patients with ICD (8th and 9th revision) codes 430-438 were collected and perused. Patients with first-ever stroke were included in the study.

RESULTS

The number of patients with first-ever stroke in the 1985-86 and 1993 surveys were 219 and 189, respectively, and 92% of them were treated at the Department of Neurology. The age-standardized (European standard population > or = 25 years) annual total stroke incidence showed a statistically significant decline over these 8 years from 317 (95% confidence interval 274-360) to 227 (95% confidence interval 194-260) per 100,000. In both studies the survival was similar with 79% of the patients surviving at 28 days after stroke onset, and 65-69% at 1 year. Recurrent strokes, 52 in 1985-86 and 50 in 1993 also showed a declining trend and no changes in survival were observed.

CONCLUSIONS

The decline in stroke mortality in Finland is best explained by the declining incidence of stroke. In the present study we did not find changes in the 1st year survival after stroke onset.

Predictors of stroke pattern in hypertensive patients

BACKGROUND AND PURPOSE

Hypertension is a recognized risk factor for stroke. However, it is not clear why hypertensive patients may have different types and causes of stroke.

METHODS

The possible role of coexisting factors was studied in 1057 patients with hypertension and first stroke admitted to a population-based stroke center. We used logistic regression analysis (multivariate and polychotomous) and the Lausanne Stroke Registry definitions of cerebral hemorrhage, cerebral infarction, lacunar infarction, cardioembolism and large artery disease.

RESULTS

Cerebral hemorrhage was not more frequent in these hypertensive patients (111/1057 = 10.5%) than in the total population of the registry (213/2145 = 10%). Cerebral infarction was associated with age above the median (69 years), diabetes, smoking history, family history of cardiac or cerebrovascular disease, hypercholesterolemia and previous TIA. In the ischemic group (n = 946), patients suffered from a lacunar infarction in 36% of the cases, large artery disease was present in 21% of them and cardioembolism in 14.5%. Large artery disease correlated with smoking history (odds ratio: 2.14; 95% confidence intervals: 1.55-2.95) and previous TIA (OR:1.96; 95% CI:1.39-2.75). Cardioembolism correlated with age over 69 years (OR:2.13; 95% CI:1.47-3.09). In patients with previous TIA and smoking history, large artery disease was presumed in 45% of the cases (vs 21%). Patients aged over 69, suffered a cardioembolic stroke in 29% of the cases (vs 14.5%). Lacunar infarction occurred in 49% of patients aged less than 70 years when no history of smoking or previous TIA was present (vs 36%).

CONCLUSION

The associations between hypertension, TIA, age and smoking history may partially explain why patients with hypertension are more likely to develop a cerebral hemorrhage, lacunar infarction, cardioembolic or a large artery disease stroke.

The alpha 1-adrenoceptor antagonist, doxazosin, modulates the lower limit of autoregulation of cerebral blood flow during hemorrhagic hypotension in anesthetized hypertensive rats

The objective of the present study was to examine the effects of administration of an alpha 1-adrenoceptor antagonist, doxazosin, for 7 days on cerebral blood flow and the autoregulatory response to hypotension in anesthetized spontaneously hypertensive rats. We determined the cerebral blood flow at rest and during hemorrhagic hypotension in 14 rats of each group using laser-Doppler flowmetry, and at the same time, the absolute baseline cerebral blood flow values at the parietal cortex were also quantified in some of the rats with the hydrogen clearance method. Baseline mean arterial pressure was significantly lowered, by 41 mm Hg, in the doxazosin-treated group, while the baseline cerebral blood flow was 31 +/- 4 ml/100 g/min(mean +/- S.D.) which was almost the same as the 32 +/- 5 ml/100 G/min in the control group. The lower limits of cerebral blood flow autoregulation were 139 +/- 9 mm Hg in the control group and 96 +/- 12 mm Hg in the treated group; the difference was significant (P < 0.001). The present results demonstrated that the lower limit of cerebral blood flow autoregulation shifts to a lower level after chronic treatment with doxazosin, an effect which is favorable for the maintenance of cerebral blood flow under hypotensive conditions.

Intracerebral hemorrhage versus infarction: stroke severity, risk factors, and prognosis

The purpose of this study was to compare stroke severity, risk factors, and prognosis in patients with intracerebral hemorrhage versus infarction. We prospectively studied 1,000 unselected patients with acute stroke of a verified type in the Copenhagen Stoke Study. Neurological deficits and functional disabilities were evaluated weekly from the time of acute admission throughout the rehabilitation period. Eighty-eight (9%) had intracerebral hemorrhage. The relative frequency of intracerebral hemorrhage rose exponentially with increasing stroke severity. In multivariate analyses, stroke type had no influence on mortality, neurological outcome, functional outcome, or the time course of recovery. Initial stroke severity was the all-important prognostic factor. The relative importance of hypertension and blood pressure on admission was not greater for intracerebral hemorrhage than for infarction. No preponderance was found between type of stroke and sex, age, and smoking. Diabetes, ischemic heart disease, and elevated serum total cholesterol level all favored cerebral infarction as opposed to intracerebral hemorrhage. We conclude that the type of stroke per se has no influence on stroke prognosis in general; the extent of the injury is decisive. The poorer prognosis in patients with intracerebral hemorrhage is due to the increase in frequency of intracerebral hemorrhage with increasing stroke severity. The likelihood of cerebral infarction occurring as opposed to intracerebral hemorrhage seems increased fivefold in stroke patients with diabetes. Hypertension and blood pressure on admission were not predictors of stroke type.

Declining trends in incidence, case-fatality and mortality of stroke in three geographic areas of Finland during 1983-1989. Results from the FINMONICA stroke register

Stroke mortality has decreased during the last decade in many industrialized countries, but there has been no clear evidence for a decline in the incidence of stroke. The present study analyzes the trends in the incidence, mortality and case-fatality of stroke in Finland from 1983 to 1989. We used data from the FINMONICA stroke register, a community based register collecting information on all suspected stroke cases aged 25-74 in three geographical areas of Finland. Annual attack rate, incidence, mortality and case-fatality rates were calculated for all strokes and for different subcategories of stroke. A linear regression model was applied to calculate the yearly trends of these rates. In men, the attack rate of stroke was 336/100,000 in 1983 and 310/100,000 in 1989 (-8% during the observation period); incidence declined from 269/100,000 in 1983 to 236/100,000 in 1989 (-12%); mortality declined from 82/100,000 to 64/100,000 (-22%), and case-fatality declined from 25% to 21% (-18%). Also among women similar declining trends were observed (-11%, -13%, -16%, and -10% respectively), but they were not statistically significant. In both incidence and mortality of stroke, the decline was seen in all age groups. Incidence and mortality of cerebral infarction declined similarly to all strokes. A large fall in the incidence (-24% in both men and women) and mortality (-38% in men and -27% in women) of subarachnoid haemorrhage was also observed. An increasing trend, although not significant, was instead observed for cerebral haemorrhage. First stroke and especially first cerebral infarction contributed most to the decline in case-fatality. The availability of computerized brain tomography improved from 18% in 1983 to 60% in 1989. We observed a fall in the incidence, mortality, and case-fatality of stroke during 1983-1989. Among the subtypes of stroke, cerebral infarction contributed most to the decline, but the data suggested also a declining trend in the incidence and mortality of subarachnoid haemorrhage, observed now for the first time in Finland since the 1960s. The fall in the incidence of stroke was not as steep during the 1980s as it was during the 1970s; Finland is anyhow the only European country which has reported a decreasing trend in stroke incidence during the 1980s. We need now to investigate how much the decline in the classical risk factors for stroke observed in Finland during the last two decades predicts the observed trends.

Trends in stroke incidence and mortality in Hawaiian Japanese men

BACKGROUND AND PURPOSE

Vital statistics show a sharp decline in stroke mortality since the late 1960s. It is not clear whether this has been associated with a decline in stroke incidence.

METHODS

Since 1966 the Honolulu Heart Program has monitored the incidence and mortality of coronary heart disease and stroke in a target population of 11,136 men of Japanese ancestry living on Oahu. Trends were analyzed from January 1, 1969, through December 31, 1988.

RESULTS

Of 7893 men aged 45 to 68 years and free of stroke at entry examination, 530 developed first episodes of stroke in the period 1969 to 1988 (389 cases of thromboembolic stroke, 124 cases of hemorrhagic stroke, and 17 cases of stroke of unknown type). Age-adjusted annual stroke incidence declined from 5.1 per 1000 person-years in 1969 to 1972 to 2.4 in 1985 to 1988. The incidences of thromboembolic stroke, hemorrhagic stroke, and total stroke decreased 3.5%, 4.2%, and 4.4% per year, respectively. The 1-month case-fatality rates for thromboembolic stroke decreased moderately; those for hemorrhagic stroke fell dramatically.

CONCLUSIONS

These findings suggest that the decline in stroke mortality in the past two or three decades results from a decline in both incidence rates and early case-fatality rates in thromboembolic and hemorrhagic stroke and stroke of unknown type. The decreases may be related to changes in risk factors, such as the decline in blood pressure and the decrease in cigarette smoking, as well as improvements in diagnosis and treatment.

Prevalence of type 2 (non-insulin-dependent) diabetes mellitus and impaired glucose tolerance in the Japanese general population: the Hisayama Study

We determined the population-based prevalence of diabetes mellitus in members of the Japanese community, Hisayama aged 40-79 years old by a 75-g oral glucose tolerance test. The basic population used to calculate diabetic prevalence was 1,077 men (72.8% of the whole population in the same age range) and 1,413 women (80.8%) including ten diabetic patients on insulin therapy. In addition, we compared the prevalence of history of diabetes which was acquired by interview or questionnaire, between participants and non-participants in the 75-g oral glucose tolerance test, but they were not statistically different. The age-adjusted prevalence of diabetes to world population was 12.7% for men and 8.4% for women, and that of impaired glucose tolerance was 19.6% for men and 18.4% for women. These figures were much higher than those previously reported from several Japanese communities. The results obtained from the present study could reveal true prevalence of diabetes among the Japanese population. In addition, the reasons for the increasing prevalence of diabetes among the recent Japanese population are also discussed.

Stroke incidence with hypertension and ischemic heart disease in Rochester, Minnesota

The primary contribution to increased incidence rates for ischemic stroke in Rochester, Minnesota, for the 1980 to 1984 time period in the age groups from 55 to 84 years was from those persons in the population with ischemic heart disease. The rate and pattern of the decline in incidence rates of ischemic stroke in hypertensive individuals and in nonhypertensive individuals were quite similar, showing no demonstrable population effect of antihypertensive medication. These observations emphasize that there must be some, as yet unidentified, factor that is important in the decline of stroke incidence.

Stroke trends in Japan

In Japan, stroke now ranks third among all causes of death following cancer and heart disease. Stroke was the leading cause of death for 3 decades after 1951. Stroke mortality tended to increase until about 1970, but it decreased and yielded first place to cancer in 1981. Heart disease deaths outnumbered stroke deaths beginning in 1985. There have not been any nationwide studies of stroke incidence in Japan, but results of studies in model areas such as Akita/Osaka, Nagano, Hiroshima/Nagasaki, and Hisayama show remarkable decreases in the incidence of cerebral infarction and cerebral hemorrhage. However, the decrease in cerebral infarction is less, especially at advanced ages where the frequency of disability is still high, and a major problem. There have not been any nationwide studies of survival rates after stroke either. In the Hiroshima/Nagasaki Study, the cumulative survival rates of cerebral hemorrhage and cerebral infarction improved from 1958 to 1969 to the period from 1970 to 1984. The decreasing incidence and mortality rates of stroke and the improving survival rate may be explained by the trends toward less severe strokes and improved medical service; however, the most influential factors are considered to be adoption of a less traditional life-style and improved blood pressure management throughout Japan.

Cerebrovascular disease at autopsy and in the death statistics for the county of Hordaland, Norway

Between 1975 and 1984 a decrease in deaths from cerebrovascular disorders was found both at autopsy and in the official mortality statistics. In the autopsy material (662 cases) the decrease was seen mainly in patients dying of cerebral hemorrhage. Concordance between autopsy and mortality statistics was best in the 30 to 79-year age group. Discordance rose with age, being highest in those above 80 years. This was mainly due to use of the diagnosis "undetermined vascular lesion" given as the clinical cause of death. The diagnosis was not upheld at autopsy. In such cases the presence of a cerebral lesion was rarely confirmed at autopsy. The decrease in acute cerebrovascular deaths was not accompanied by an increase in the number of patients in the category "stroke with sequelae", assessed as a fall in number. Thus mortality statistics can be directly misleading in geriatric patients; and the autopsy frequency in this age group is too low to give a satisfactory picture of events.

Marked increase of stroke incidence in men between 1972 and 1990 in Frederiksberg, Denmark

BACKGROUND AND PURPOSE

Stroke incidence declined until the end of the 1970s in the United States, and the decline continued into the 1980s in Japan. The purpose of this study was to determine possible temporal changes of stroke incidence in a European community.

METHODS

A prospective stroke registry was established in the community of Frederiksberg (population, approximately 90,000), Denmark, in the two periods 1972-1974 and 1989-1990. All patients suspected of stroke were clinically evaluated by a neurologist. Only patients with first-ever stroke were included. Complete case ascertainment was ensured by registration of both hospitalized and nonhospitalized patients. Death certificates were also scrutinized.

RESULTS

A total of 927 patients with first-ever stroke was recorded. The annual stroke incidence rate per 1,000 increased by 18% from 2.6 in 1972-1974 to 3.1 in 1989-1990 (p < 0.01). This increase was due solely to a 42% increase in men, in whom stroke incidence rose from 2.1 to 3.0 (p < 0.0005). Incidence was unchanged in women at 3.0 and 3.1, respectively. The incidence rates from 1972-1974 were age and sex adjusted to the 1990 population. After adjustment to the Danish population, stroke incidence in Denmark was 2.0 for all, 2.3 for men, and 1.9 for women. In the second study period computed tomography or necropsy was performed in 85% of cases; 2.4/1,000 had cerebral infarction; 0.20/1,000 had intracerebral hemorrhage; and 0.02/1,000 had subarachnoid hemorrhage.

CONCLUSIONS

In a period when decline in stroke incidence has stopped in the United States and has continued in Japan, a marked increase of stroke incidence in Danish men was observed.

Stroke incidence rates were unchanged, while fatality rates declined, during 1971-1987 in Göteborg, Sweden

BACKGROUND AND PURPOSE

Stroke risk factors have been shown to change with time in several places; simultaneously, stroke incidence rates have increased in some and decreased in other places. In Göteborg, Sweden, cardiovascular epidemiological research has included stroke registration since 1971. From these data on stroke, incidence and fatality rates from a 17-year period are given.

METHODS

During the period 1971-1987 all cases of stroke occurring in people aged 15-65 years in the city of Göteborg were uniformly recorded, with an estimated case detection rate of 90% or more.

RESULTS

Age-adjusted incidence rates of first-ever stroke by sex did not change during the period. Age-specific rates and rates for individual types of stroke (subarachnoid hemorrhage, intracerebral hemorrhage, and cerebral infarction-unspecified stroke combined) were also largely unchanged. A slight increase in the incidence rate of intracerebral hemorrhage may be due to better detection after computed tomography came into use in 1976. Stroke fatality rates declined through the whole period in both sexes and all age groups, markedly so for intracerebral hemorrhage and subarachnoid hemorrhage.

CONCLUSIONS

This conforms with vital statistics for Göteborg and for Sweden of declining stroke mortality during the period. The decline in stroke fatality rates may be related to decreases in smoking habits and blood pressure together with an increase in the percentage of people on antihypertensive treatment among middle-aged men, and to some extent even middle-aged women, reported from the same population. Why stroke incidence rates did not decline concomitantly is unexplained.

Prevalence and etiology of dementia in a Japanese community

BACKGROUND AND PURPOSE

We sought to determine the type-specific prevalence of dementia and its risk factors in elderly persons from the Japanese community of Hisayama.

METHODS

We studied the prevalence of dementia in 887 Hisayama residents (353 men and 534 women) aged 65 years or older (screening rate, 94.6%) using various items of clinical information, neurological examination, and dementia scales. We also studied brain morphology in 50 of 59 determined to have dementia by computed tomography or autopsy during the subsequent 54-month period. Factors relevant to dementia were compared between 27 patients with vascular dementia and 789 control subjects without dementia in a retrospective fashion.

RESULTS

The prevalence rate of dementia among Hisayama residents aged 65 or older was estimated at 6.7%, with a females to males ratio of 1:2. Among 50 cases of dementia in which brain morphology was examined, the frequency of vascular dementia was 56%; this rate was 2.2 times higher than that for senile dementia of the Alzheimer type. Aging, hypertension, electrocardiographic abnormalities, and high hematocrit were significantly (p less than 0.05) and independently associated with the occurrence of vascular dementia.

CONCLUSIONS

Prevalence of dementia among the Hisayama residents was relatively identical to that previously reported, but vascular dementia was more predominant. Risk factors for vascular dementia were similar to those for lacunar infarcts. Control of hypertension may be a key to reducing dementia among the Japanese population.

Stroke registry in Malmö, Sweden

BACKGROUND AND PURPOSE

A stroke registry covering the city of Malmö, Sweden (population 232,000) was started in January of 1989 to prospectively follow up stroke incidence, recurrence, and fatality rates.

METHODS

Patients with presumed stroke were interviewed within 1 week after admission to the hospital, and their medical records were examined. Continuous validation against hospital diagnosis showed well over 90% of all stroke cases in Malmö to have been included.

RESULTS

Incidence rates per 100,000 residents were 300 for all stroke events and 225 for first-ever stroke, lower than those reported from other studies. The distribution of stroke diagnostic categories was 3% subarachnoid hemorrhage, 10% intracerebral hemorrhage, 50% cerebral infarction, and 38% unspecified stroke. The diagnosis was based on computed tomography in 51% of first-ever stroke cases. Median age was 73.1 years for men and 79.7 years for women. Incidence rates for all stroke diagnostic categories except subarachnoid hemorrhage increased with age. Prior stroke, hypertension, smoking, atrial fibrillation, and diabetes mellitus were major risk factors for all stroke events. The presenting symptoms were hemiparesis in 74%, speech disorder in 49%, and clouded consciousness in 19% of the patients. The overall case-fatality rate at 30 days was 15%; the rate for intracerebral hemorrhage was 37% and that for cerebral infarction was 10%.

CONCLUSIONS

Our findings confirm the value of a stroke registry for stroke epidemiology purposes and as a tool for specific stroke research.

Stroke incidence in Copenhagen, 1976-1988

BACKGROUND AND PURPOSE

Temporal trends in stroke incidence in Denmark have not been previously reported. The Copenhagen City Heart Study is a prospective study based on a randomly selected sample of an urban population of, initially, 19,698 participants followed since 1976. Over a period of 12 years, we studied three important aspects of stroke incidence in 848 identified cases: temporal trends, dependence on age and sex, and comparison of responders and nonresponders.

METHODS

The participants were invited to two health examinations at 5-year intervals. The participants who attended at least one of the two examinations are termed responders and those who attended none nonresponders. The cases of first-ever stroke were collected from responders, the National Patient Register, and the National Register of Deaths and were verified by study of hospital records and death certificates.

RESULTS

For responders aged 35-64 years and greater than or equal to 65 years, there were no significant changes in the weighted rates in four consecutive 3-year periods. There was a tendency toward decreasing rates among younger women, but not in older women or men. The age- and sex-adjusted rates per 1,000 (based on the Danish population in 1982) in responders in the entire 12-year follow-up period were 1.61 in women, 2.67 in men, and 2.14 in both sexes combined. Stroke incidence rates increased exponentially with age in both sexes, with rates in men generally twice those in women, even in the greater than or equal to 75 years of age group. Age-adjusted rates were higher in nonresponders than in responders. For women, this ratio was 1.7; for men, 1.1.

CONCLUSIONS

The stroke incidence in Copenhagen is relatively high and has shown no decreasing tendency over the period 1976-1988.

Smoking as cardiovascular risk factor in low cholesterol population: the Hisayama Study

Cigarette smoking as a risk factor for cerebro- and cardiovascular diseases was studied in a long-term prospective population survey which has been carried out in a Japanese rural community, Hisayama. In this population, the incidence of thrombotic brain infarction (TBI) was much higher than that of coronary heart disease (CHD) over a 26-year follow-up period. Cigarette smoking was strongly related to the occurrence of CHD but not to TBI. Comparing the incidence of CHD and TBI between first or early cohort (1961-74) and second or recent cohort (1974-87) during the 13-year follow-up, the incidence remained unchanged for CHD, while it significantly decreased for TBI in recent population. The prevalence of cigarette smoking as well as hypertension decreased in recent years, while hypercholesterolemia, obesity, and glucose intolerance increased. Smoking is a major contributor to CHD for men in both cohorts, but it is not any more for women in the recent cohort.

Cerebrovascular disease in Saudi Arabia

We studied the pattern and outcome of strokes in 200 Saudi patients. Cerebral infarction constituted 87% of strokes, subarachnoid hemorrhage 4.5%, cerebral hemorrhage 6.5%, and venous infarction 2%. The vessel most commonly involved was part or all of the middle cerebral artery, constituting 52% (90) of the 174 arterial infarcts. Lacunar infarcts were seen in 21% (37) of the patients with arterial infarcts. Among all 200 patients, 8% died and 8% had secondary generalized seizures. Hypertension occurred in 41% of the 174 patients with arterial infarcts and 62% of the 13 with cerebral hemorrhages. The highest incidence of hypertension as a risk factor was among those with lacunar infarcts (81%), ganglionic cerebral hemorrhages (80%), and infarcts of deep branches of the middle cerebral artery (57%). Embolic infarcts due to rheumatic heart disease constituted 11% of all arterial infarcts. We conclude that our pattern of strokes is similar to that of the west rather than that of the Japanese, but with less frequent arteriovenous malformations and aneurysms.

Cerebral haemorrhage in a French prospective population study

The incidence of cerebral haemorrhage was studied from a population-based stroke registry. The incidence was 12.3 per 100,000 per year in women and 13.9 per 100,000 per year in men, with a peak in the eighth decade and a male preponderance. Haemorrhages were deep seated and mostly due to hypertension. Recognised clinical characteristics of haemorrhage are acute onset, convulsion, vomiting, and disturbed consciousness. This study showed that cerebral haemorrhage may present with pure motor deficit or transient deficit preceding the stroke. The mortality was 51% in the first month, and 61% by two years.

Causes of death in the elderly and their changing pattern in Hisayama, a Japanese community. Results from a long-term and autopsy-based study

The causes of death for the elderly were prospectively studied in Hisayama, Japan, a rural community. We compared 1,621 subjects, aged 40 years or over, recruited in 1961, and 2,053 subjects recruited in 1974. Each cohort was studied in a follow-up that lasted 10 years; they had autopsy rates of 82.1% and 86.1% during each 10-year period, respectively. The most common causes of death for those aged 70 years or over were cerebrovascular disease, malignant neoplasms, and pneumonia. Deaths due to cerebrovascular disease tended to decrease in the recent cohort, but the proportion of decline was more prominent in cases aged 40 to 69 years. There was a sex difference in the changing pattern of mortality from heart diseases including ischemic heart disease. Deaths by both heart diseases and ischemic heart disease increased in the more recent cohort of aged women, whereas they decreased in the aged men. Pneumonia was an important cause of death for the elderly in both cohorts. Deaths due to "senility" were rare, being only 1% of the deceased aged 70 or over. With prolonged lifespan, especially for women, the impact of atherosclerosis and its related disorders on the recent Japanese aged population appears to have increased.

The frequency, causes and timing of death within 30 days of a first stroke: the Oxfordshire Community Stroke Project

In a prospective, community-based study of 675 consecutive patients with a first-ever stroke, of whom over 90% had computed tomography (CT) and/or necropsy examinations, 129 deaths occurred within 30 days of the onset of symptoms, a case fatality rate (CFR) of 19%. The 30 day CFR for patients with cerebral infarction was 10% (57 of 545, for primary intracerebral haemorrhage 52% (34 of 66), for subarachnoid haemorrhage 45% (15 of 33) and for those of uncertain pathological type 74% (23 of 31). The CFR for patients who had been functionally dependent pre-stroke was 33% compared with 17% for those who had been independent pre-stroke. The age-adjusted relative risk of death for patients who had been functionally dependent pre-stroke was not significantly greater (1.8, 95% confidence interval 0 to 4.3). There was a significant trend for CFR to increase with age (Chi square for trend = 4.0, p less than 0.05). This relationship was found in those patients who had been functionally independent prestroke (Chi square for trend = 7.9, p less than 0.005) but not in those who had been dependent pre-stroke (Chi square for trend = 0.5, NS). The pattern of increasing CFR with increasing age amongst those who had been independent prestroke was seen particularly in patients with cerebral infarction (Chi square for trend = 8.6, p less than 0.005). The age-adjusted relative risk of death for patients with cerebral infarction who had been functionally dependent pre-stroke was 2.2 (95% confidence interval 1.2 to 4.1). Fifty three percent of all deaths within 30 days of stroke were due to the direct neurological sequelae of the stroke. Patients with primary intracerebral or subarachnoid haemorrhages were significantly more likely to die in this way than those with cerebral infarction (relative risk 4.1; 95% confidence interval 3.4-4.9) and 56% of such deaths occurred within 72 hours of onset. In patients with cerebral infarction, 51% of deaths were due to complications of immobility (for example, pneumonia, pulmonary embolism) and these were more likely to occur after the first week. These findings have implications for clinical practice and the planning of clinical trials.