Stroke Mortality In Japan Research Articles

Access to mechanical thrombectomy and ischemic stroke mortality in Japan: a spatial ecological study.

Advances in stroke treatment have greatly improved outcomes; however, disparities in access to treatment might increase. Achieving equitable access to stroke treatment is a health policy challenge, as rapid treatment is essential for positive outcomes. This ecological cross-sectional study aimed to determine the relationship between the disparities in spatial accessibility to mechanical thrombectomy (SAMT) and stroke mortality rates in Japan, hypothesizing that disparities in SAMT may increase the differences in stroke mortality between regions. We used the average number of ischemic stroke (IS) deaths between 2020 and 2021 as the response variable; and SAMT, medical resources, and socioeconomic characteristics of each municipality as explanatory variables. A conditional autoregressive model was used to examine the association between the risk of stroke mortality and SAMT. The standardized mortality ratio (SMR) was mapped to understand the nationwide disparities in stroke mortality risk. The median number of IS deaths was 17.5 persons per year in the municipalities (2020 to 2021). The study also found that municipalities with low SAMT were located in the northern part of Japan. The non-spatial regression model results indicated that poor accessibility, a small proportion of bachelor's degrees or higher, and a high proportion of workers in secondary industries were related to high IS mortality. Three models were evaluated using spatial analysis; Model 1 with accessibility indicators alone, Model 2 with medical resources added to Model 1, and Model 3 with socioeconomic characteristics added to Model 2. In Models 1 and 2, the population-weighted spatial accessibility index (PWSAI) showed a significant negative relationship with stroke mortality. However, this was not evident in Model 3. Mapping using Model 3 showed that the high-risk areas were predominantly located in northern Japan, excluding Hokkaido. Access to mechanical thrombectomy was estimated, and regional differences were observed. The relationship between accessibility and IS mortality is unknown; however, regardless of accessibility, municipalities with a high proportion of workers in secondary industries and a small proportion with bachelor's degrees or above are at risk of death from stroke.

Projections of future coronary heart disease and stroke mortality in Japan until 2040: a Bayesian age-period-cohort analysis

We aimed to estimate the future burden of coronary heart disease (CHD) and stroke mortalities by sex and all 47 prefectures of Japan until 2040 while accounting for effects of age, period, and cohort and integrating them to be at the national level to account for regional differences among prefectures. We estimated future CHD and stroke mortality projections, developing Bayesian age-period-cohort (BAPC) models in population and the number of CHD and stroke by age, sex, and all 47 prefectures observed from 1995 to 2019; then applying these to official future population estimates until 2040. The present participants were all men and women aged over 30 years and were residents of Japan. In the BAPC models, the predicted number of national-level cardiovascular deaths from 2020 to 2040 would decrease (39,600 [95% credible interval: 32,200-47,900] to 36,200 [21,500-58,900] CHD deaths in men, and 27,400 [22,000-34,000] to 23,600 [12,700-43,800] in women; and 50,400 [41,900-60,200] to 40,800 [25,200-67,800] stroke deaths in men, and 52,200 [43,100-62,800] to 47,400 [26,800-87,200] in women). After adjusting these factors, future CHD and stroke deaths will decline until 2040at the national level and in most prefectures. This research was supported by the Intramural Research Fund of Cardiovascular Diseases of the National Cerebral and Cardiovascular Center (21-1-6, 21-6-8), JSPS KAKENHI Grant Number JP22K17821, and the Ministry of Health, Labour and Welfare Comprehensive Research on Life-Style Related (Diseases Cardiovascular Diseases and Diabetes Mellitus Program), Grant Number 22FA1015.

Ramen restaurant prevalence is associated with stroke mortality in Japan: an ecological study

BackgroundThe association between stroke and nutrition has recently been investigated. However, the association between diet and stroke in Japan has not been clarified. We hypothesized that there may be an association between consumption of ramen and stroke mortality. Therefore, we investigated the association between the prevalence of ramen restaurants and stroke mortality in Japanese prefectures.MethodsWe used Pearson’s correlation coefficients to evaluate associations between the prevalence of each of four restaurant types (ramen, fast food, French or Italian, and udon or soba) and age- and sex-adjusted stroke mortality rates in each prefecture. We also investigated correlations between acute myocardial infarction and the prevalence of each type of restaurant as a control. We obtained age- and sex-adjusted stroke mortality rates and the acute myocardial infarction mortality rate in each prefecture from the 2017 Trends in National Health published in Japan. Data on the number of restaurants of each type in each prefecture were obtained from the database of the Nippon Telegraph and Telephone Corporation.ResultsThe prevalence of ramen restaurants, but not of other restaurant types, positively correlated with stroke mortality in both men and women (r > 0.5). We found no correlation between ramen restaurant prevalence and mortality from acute myocardial infarction.ConclusionThe prevalence of ramen restaurants in Japanese prefectures has a significant correlation with the stroke mortality rate.

Spatial and Temporal Features of Heat Stroke Mortality in Japan and Their Relation to Temperature Variations, 1999–2014

Spatial and Temporal Features of Heat Stroke Mortality in Japan and Their Relation to Temperature Variations, 1999–2014

Variation in Risk-Standardized Mortality of Stroke among Hospitals in Japan.

Despite recent advances in care, stroke remains a life-threatening disease. Little is known about current hospital mortality with stroke and how it varies by hospital in a national clinical setting in Japan. Using the Diagnosis Procedure Combination database (a national inpatient database in Japan), we identified patients aged ≥20 years who were admitted to the hospital with a primary diagnosis of stroke within 3 days of stroke onset from April 2012 to March 2013. We constructed a multivariable logistic regression model to predict in-hospital death for each patient with patient-level factors, including age, sex, type of stroke, Japan Coma Scale, and modified Rankin Scale. We defined risk-standardized mortality ratio as the ratio of the actual number of in-hospital deaths to the expected number of such deaths for each hospital. A hospital-level multivariable linear regression was modeled to analyze the association between risk-standardized mortality ratio and hospital-level factors. We performed a patient-level Cox regression analysis to examine the association of in-hospital death with both patient-level and hospital-level factors. Of 176,753 eligible patients from 894 hospitals, overall in-hospital mortality was 10.8%. The risk-standardized mortality ratio for stroke varied widely among the hospitals; the proportions of hospitals with risk-standardized mortality ratio categories of ≤0.50, 0.51–1.00, 1.01–1.50, 1.51–2.00, and >2.00 were 3.9%, 47.9%, 41.4%, 5.2%, and 1.5%, respectively. Academic status, presence of a stroke care unit, higher hospital volume and availability of endovascular therapy had a significantly lower risk-standardized mortality ratio; distance from the patient’s residence to the hospital was not associated with the risk-standardized mortality ratio. Our results suggest that stroke-ready hospitals play an important role in improving stroke mortality in Japan.

Abstract WP387: Stroke Mortality In Japan Increases On Weekends Altough Those In Comprehensive Stroke Centers Remain Unchanged. -J-ASPECT Study

Objective Weekend disparities in stroke care were well known. The aim of this study is to examine the association between day of admission and the mortality of Stroke in Japan. Moreover, we examine if comprehensive stroke center (CSC) could overcome the weekend effect. Methods We analyzed the Nationwide registry of claim data(J-ASPECT study) in 378 certified training institutions of the Japan Neurosurgical Society and/or the Japan Stroke Society, which included patients discharged with a primary diagnosis of cerebral infarction in 2011. The definition of CSC was followed by the article of McKinney et al. (Stroke. 2011;42:2403-2409.) Results A total of 68,718 patients were admitted with a primary diagnosis of cerebral infarction during the study period while 10,141 patients were admitted to comprehensive stroke centers. As a result, thirty-day mortality was statistically greater in patients admitted on weekends compared to weekdays (9.1% versus 8.3%; P = 0.0004). The age and sex adjusted risk of death at 30 days which derived from multivariate logistic regression were also significantly greater for weekend admission (odds ratio, OR= 1.11; 95% CI, 1.04 to 1.18). This association was robust using hierarchical logistic regression which adjusted for institute difference. (OR= 1.06, 95% CI, 1.01 to 1.12) .The mortality of patients in hospitals with stroke care units showed no difference between weekends and weekdays (p=0.398) while the difference was significant for patients, not in a stroke care unit (p=0.046).Furthermore, there was no significant difference in 30-day mortality for patients admitted to CSCs between weekends and weekdays (p=0.418) while patients who were not admitted to CSCs showed the significant mortality difference between weekends and weekdays (p=0.041). The risk of mortality was 2% decreased with the satisfaction of every one criterion for comprehensive stroke care unit. (OR=0.98, 95% CI 0.97 to 0.99) adjusted for weekend effect. Conclusions Patients with stroke admitted on weekends in Japan had a significantly higher risk of death than weekdays within 30 days. There was no significant weekend difference of stroke mortality at hospitals with stroke care units and comprehensive stroke centers.

Abstract WP396: Effects of the Accessibility to Emergency Medical Systems on Stroke Mortality: A Nationwide Survey (J-ASPECT study)

Objective: Rapid emergency medical care for patients with acute stroke is necessary for better prognoses. To decrease the time to medical care, emergency medical systems (EMSs) and stroke centers are distributed extensively in Japan, with universal coverage of medical insurance. We examined the influence of the accessibility to EMSs on stroke mortality in Japan. Methods: We approached 1381 certified training institutions of the Japan Neurosurgical Society and/or the Japan Stroke Society with a question survey regarding acute stroke care capacity. In institutions that responded, the data of the stroke patients hospitalized were obtained from Japanese Diagnosis Procedure Combination database of 2011. The transfer time was measured by an electronic mapping system as the time taken from the postal address of the patient to the transferred hospital. Geographical location by urban employment area (UMA) was classified into 5 categories: metropolitan employment areas (MEA) - central, MEA - outlying, micropolitan employment areas (McEA) - central, McEA - outlying, and unclassified. We examined the effects of UMA and transfer time as measures of accessibility by using a hierarchical linear regression model adjusted by age, gender, and characteristics of institutions. Results: The data of 256 institutions and 53,170 emergency hospitalized patients were analyzed. Mortalities were as follows: 7.8% in cerebral infarction (n = 32,671); 16.8% in intracerebral hemorrhage (n = 15,699); and 28.1% in subarachnoid hemorrhage (n = 4,934). The mortality was lower in MEA - central and higher in unclassified areas for mortality in cerebral infarction (MEA - central, 7.3%; unclassified, 12.0%; OR = 1.55, 95%CI = 1.01-2.39) and subarachnoid hemorrhage (MEA - central, 26.7%; unclassified, 42.9%; OR = 1.95, 95%CI = 1.03-3.70). In areas in cerebral infarction, longer transfer time affected mortality (P = 0.027, MEA - central; P = 0.038, unclassified). Conclusion: Stroke mortality increased according to the inaccessibility to EMS combined with UMA and transfer time. These factors should be taken into account to resolve inappropriate EMS disparities.

Cardiovascular Disease Epidemiology in Asia

Cardiovascular disease (CVD) is the leading cause of death in the world and half of the cases of CVD are estimated to occur in Asia. Compared with Western countries, most Asian countries, except for Japan, South Korea, Singapore and Thailand, have higher age-adjusted mortality from CVD. In Japan, the mortality from CVD, especially stroke, has declined continuously from the 1960s to the 2000s, which has contributed to making Japan into the top-ranking country for longevity in the world. Hypertension and smoking are the most notable risk factors for stroke and coronary artery disease, whereas dyslipidemia and diabetes mellitus are risk factors for ischemic heart disease and ischemic stroke. The nationwide approach to hypertension prevention and control has contributed to a substantial decline in stroke mortality in Japan. Recent antismoking campaigns have contributed to a decline in the smoking rate among men. Conversely, the prevalence of dyslipidemia and diabetes mellitus increased from the 1980s to the 2000s and, therefore, the population-attributable risks of CVD for dyslipidemia and diabetes mellitus have increased moderately. To prevent future CVD in Asia, the intensive prevention programs for hypertension and smoking should be continued and that for emerging metabolic risk factors should be intensified in Japan. The successful intervention programs in Japan can be applied to other Asian countries.

Poster #88 CHILDHOOD INFECTION AND SCHIZOPHRENIA AND OTHER PSYCHOSIS: A SYSTEMATIC REVIEW AND META-ANALYSIS OF POPULATION-BASED STUDIES

Background: Although stroke mortality has been decreasing in Japan, in 2000 it was still the third leading cause of death among Japanese of either sex. Elucidation of stroke mortality trends among age, calendar year, and birth cohorts should improve stroke prevention efforts. The objective of this study was to clarify the age, period, and cohort effects on stroke mortality in Japan from 1960 to 2000 by using stratified age-period-cohort models with improved goodness of fit. Methods: Death and population from the Vital Statistics of Japan and the National Statistics Bureau, respectively, were tabulated among 12 age groups (30-34, 35-39, 40-44, 45-49, 50-54, 55-59, 60-64, 65-69, 70-74, 75-79, 80-84, and 85-89) and 9 quinquennials (1960, 1965, 1970, 1975, 1980, 1985, 1990, 1995, and 2000), which yielded 20 birth cohorts (midyears of 1873, 1878, 1883, 1888, 1893, 1898, 1903, 1908, 1913, 1918, 1923, 1928, 1933, 1938, 1943, 1948, 1953, 1958, 1963, and 1968). A stratified model (age-periods-cohort model) with 7 age classes (30-44, 45-54, 55-64, 65-69, 70-74, 75-79, and 80-89 years) was applied under the assumption that the number of deaths has an extra-Poisson variation. Results: The stratified model showed that: (1) middle-aged groups (40-64 years in men and 40-59 years in women) had higher mortality than their linear age trends; (2) young (30-44 years) and middle-aged (45-64 years) groups showed different patterns than those of the elderly (65-89 years) age groups: the two younger groups had higher nonlinear period effects than their linear trends between 1970 and 1990, and the trend of decreasing began later (in 1975 in men and 1980 in women, respectively) than it did for the elderly (1970); and (3) the nonlinear cohort effects indicated 4 patterns in each sex, and the effects increased in post-1948 cohort in men and in post-1958 cohort in women. Conclusion: Young and middle age (30-59 years) boosted the mortality, suggesting that this age range should be targeted for increased stroke prevention efforts.

Premature mortality due to stroke and trend in stroke mortality in Japan (1980-2005)

Although a downward trend in stroke mortality over the last decades has been observed in many countries, stroke remains an important contributor to the total burden of disease. In the present study, we provided additional measures, namely years of life lost (YLLs) and average years of life lost (AYLLs) to reflect the burden of this condition in Japan. We obtained stroke mortality data for Japan from the World Health Organization mortality database for the period 1980-2005 to analyze trends of age-standardized rates (ASRs) per 100,000 of stroke mortality. YLLs and AYLLs were also estimated according to Japanese life tables. Decreases in ASRs by 68% in men and by 74% in women were observed at the end of this study period. In men, there were total of 1,684,482 YLLs in 1980; 776,350 in 1995 and 745,636 in 2005, corresponding to an overall AYLLs for all stroke deaths of 20.6; 11.2 and 11.7 years earlier than expected, respectively. In women, the respective numbers were 1,567,817 YLLs in 1980; 810,135 in 1995 and 726,650 in 2005, corresponding to an overall AYLLs for all stroke deaths of 19.4; 10.5 and 10.5 years. The findings showed shorter AYLLs due to stroke in Japan, suggesting that stroke patients died from this condition at older age at the end of the study period. This change in premature mortality was consistent with decreased trend in the stroke mortality.

大規模コホート研究の知見：ＮＩＰＰＯＮ ＤＡＴＡより

The NIPPON DATA is a large-scale cohort study based on a representative Japanese population for men and women aged 30 years and over who were randomly selected through out Japan. The NIPPON DATA80 and the NIPPON DATA90 comprise about 10,000 and 8,000 participants, respectively. The baseline surveys were conducted in 1980 and 1990, respectively. These tow cohorts have been followed up to the year 2004 and 2005, respectively and cause specific deaths were determined by linking with the government mortality statistics in Japan with proper permission. Here, the findings of the 19-year follow-up from NIPPON DATA80 are mainly described. For the relationship between blood pressure and stroke mortality; the higher the blood pressure level, the higher the risk of stroke mortality. Compared with the category of the optimal blood pressure level (systolic blood pressure (SBP) /diastolic blood pressure (DBP), <120/<80 mmHg) defined by the Joint National Committee, USA (JNC6), stroke mortality risk for the category of high blood pressure (SBP≥180 mmHg and/or DBP 110 mmHg) was 5-fold higher. For men, the significant graded and positive relationship of SBP with the risk of cardiovascular disease (CVD) death was observed from the young to the old age group (30-64 years, 65-74 years, and 75 years and more). Age-adjusted stroke mortality in Japan has declined by around 80% during the period of 1965-1990, and this has been observed with a concomitant great decline in population blood pressure level. In conclusion, it is very important for people to keep their blood pressure levels in control all along their life by maintaining healthy lifestyles.

Stratified Age-Period-Cohort Analysis of Stroke Mortality in Japan, 1960 to 2000

Although stroke mortality has been decreasing in Japan, in 2000 it was still the third leading cause of death among Japanese of either sex. Elucidation of stroke mortality trends among age, calendar year, and birth cohorts should improve stroke prevention efforts. The objective of this study was to clarify the age, period, and cohort effects on stroke mortality in Japan from 1960 to 2000 by using stratified age-period-cohort models with improved goodness of fit. Death and population from the Vital Statistics of Japan and the National Statistics Bureau, respectively, were tabulated among 12 age groups (30-34, 35-39, 40-44, 45-49, 50-54, 55-59, 60-64, 65-69, 70-74, 75-79, 80-84, and 85-89) and 9 quinquennials (1960, 1965, 1970, 1975, 1980, 1985, 1990, 1995, and 2000), which yielded 20 birth cohorts (midyears of 1873, 1878, 1883, 1888, 1893, 1898, 1903, 1908, 1913, 1918, 1923, 1928, 1933, 1938, 1943, 1948, 1953, 1958, 1963, and 1968). A stratified model (age-periods-cohort model) with 7 age classes (30-44, 45-54, 55-64, 65-69, 70-74, 75-79, and 80-89 years) was applied under the assumption that the number of deaths has an extra-Poisson variation. The stratified model showed that: (1) middle-aged groups (40-64 years in men and 40-59 years in women) had higher mortality than their linear age trends; (2) young (30-44 years) and middle-aged (45-64 years) groups showed different patterns than those of the elderly (65-89 years) age groups: the two younger groups had higher nonlinear period effects than their linear trends between 1970 and 1990, and the trend of decreasing began later (in 1975 in men and 1980 in women, respectively) than it did for the elderly (1970); and (3) the nonlinear cohort effects indicated 4 patterns in each sex, and the effects increased in post-1948 cohort in men and in post-1958 cohort in women. Young and middle age (30-59 years) boosted the mortality, suggesting that this age range should be targeted for increased stroke prevention efforts.

Relation of Adult Height With Stroke Mortality in Japan

The age-adjusted stroke mortality rate in Japan was the highest in the world from 1950 to the 1970s, but it started to dramatically decrease after 1965. In addition to improved management of high blood pressure, the increase in average height might also contribute to this reduction. The present study investigates whether height is an independent risk for stroke mortality in Japan. Among participants of the National Survey on Cardiovascular Diseases in 1980 who were randomly selected from the Japanese population, we followed up 3969 and 4955 Japanese men and women without prior cardiovascular disease for a maximum of 19 years and observed 158 and 132 stroke deaths. Height was inversely correlated with age and with crude stroke mortality. The relationship was attenuated in men when we adjusted for age or other possible confounders (multivariate adjusted relative hazards of a 5-cm increase of height for stroke mortality: 0.92, 95% CI: 0.79 to 1.08). For women, the inverse relationship (relative hazard: 0.77: 95% CI: 0.64 to 0.91) remained after multivariate adjustment. These relationships persisted when we stratified participants by age. Height is inversely related to stroke mortality and the relationship is statistically significant among Japanese women.

IP-0046 Long-term outcome of direct coronary stenting of left main coronary artery stenoses

Background: Although stroke mortality has been decreasing in Japan, in 2000 it was still the third leading cause of death among Japanese of either sex. Elucidation of stroke mortality trends among age, calendar year, and birth cohorts should improve stroke prevention efforts. The objective of this study was to clarify the age, period, and cohort effects on stroke mortality in Japan from 1960 to 2000 by using stratified age-period-cohort models with improved goodness of fit. Methods: Death and population from the Vital Statistics of Japan and the National Statistics Bureau, respectively, were tabulated among 12 age groups (30-34, 35-39, 40-44, 45-49, 50-54, 55-59, 60-64, 65-69, 70-74, 75-79, 80-84, and 85-89) and 9 quinquennials (1960, 1965, 1970, 1975, 1980, 1985, 1990, 1995, and 2000), which yielded 20 birth cohorts (midyears of 1873, 1878, 1883, 1888, 1893, 1898, 1903, 1908, 1913, 1918, 1923, 1928, 1933, 1938, 1943, 1948, 1953, 1958, 1963, and 1968). A stratified model (age-periods-cohort model) with 7 age classes (30-44, 45-54, 55-64, 65-69, 70-74, 75-79, and 80-89 years) was applied under the assumption that the number of deaths has an extra-Poisson variation. Results: The stratified model showed that: (1) middle-aged groups (40-64 years in men and 40-59 years in women) had higher mortality than their linear age trends; (2) young (30-44 years) and middle-aged (45-64 years) groups showed different patterns than those of the elderly (65-89 years) age groups: the two younger groups had higher nonlinear period effects than their linear trends between 1970 and 1990, and the trend of decreasing began later (in 1975 in men and 1980 in women, respectively) than it did for the elderly (1970); and (3) the nonlinear cohort effects indicated 4 patterns in each sex, and the effects increased in post-1948 cohort in men and in post-1958 cohort in women. Conclusion: Young and middle age (30-59 years) boosted the mortality, suggesting that this age range should be targeted for increased stroke prevention efforts.

Epidemiology of hypertension in China and Japan.

Hypertension is a major risk factor for cardiovascular disease in Chinese and Japanese with a low to moderate serum cholesterol level. The prevalence of hypertension is diverse in Chinese populations with different geographic region, lifestyles and cultures. The same diversity was observed in Japan in the past, but recently the regional difference has become smaller. The large decline in stroke mortality in Japan was followed by a reduction in the prevalence of hypertension and the lowering level of blood pressure. This is partly explained by various community-based hypertension control programmes. Chinese populations are now showing similar patterns as those observed in Japan. These populations still have high proportions of undetected hypertensives and untreated patients in China. In both Chinese and Japanese, high salt consumption is one of the most important risk factors for hypertension. In addition to this, the increase in body weight, smoking and alcohol consumption in Chinese people seems to be the major factors for the increasing trends in hypertension. Control of hypertension and lowering blood pressure in the population level should be the important strategies for the prevention of cardiovascular disease in Chinese and Japanese.

Trends in stroke incidence and acute case fatality in a Japanese rural area : the Oyabe study.

Stroke mortality in Japan has significantly declined during recent decades. To determine the cause of this decrease, we studied the trends in stroke incidence and case fatality within 28 days after stroke in a rural area in Japan. We used a population-based registry during 1977-1991 in Oyabe, a rural area in the central part of Japan. The average population aged 25 years and older numbered 32 859 persons. Changes in age-standardized stroke incidence rate were calculated and compared between the 3 periods 1977-1981, 1982-1986, and 1987-1991. The 28-day case fatality rate was evaluated and also compared between the 3 periods by onset year. The total number of strokes was 2068. The age-standardized incidence rate of all strokes decreased during the 15-year period, from 605 to 417 per 100 000 in men and from 476 to 329 per 100 000 in women. A marked decline was found during 1977-1986 but was not apparent during 1987-1991. Moreover, there was an increase in the group aged 75 years and older. The 28-day case fatality rates for all strokes improved from 18.0% to 14.2% in men and from 26.8% to 19.1% in women during the observation period. These data indicate that declines in the stroke incidence and the 28- day case fatality have been associated with a marked decrease in stroke-related mortality in Japan.

Psychotropic drug use in old age (results of the Berlin aging study)

Background: Although stroke mortality has been decreasing in Japan, in 2000 it was still the third leading cause of death among Japanese of either sex. Elucidation of stroke mortality trends among age, calendar year, and birth cohorts should improve stroke prevention efforts. The objective of this study was to clarify the age, period, and cohort effects on stroke mortality in Japan from 1960 to 2000 by using stratified age-period-cohort models with improved goodness of fit. Methods: Death and population from the Vital Statistics of Japan and the National Statistics Bureau, respectively, were tabulated among 12 age groups (30-34, 35-39, 40-44, 45-49, 50-54, 55-59, 60-64, 65-69, 70-74, 75-79, 80-84, and 85-89) and 9 quinquennials (1960, 1965, 1970, 1975, 1980, 1985, 1990, 1995, and 2000), which yielded 20 birth cohorts (midyears of 1873, 1878, 1883, 1888, 1893, 1898, 1903, 1908, 1913, 1918, 1923, 1928, 1933, 1938, 1943, 1948, 1953, 1958, 1963, and 1968). A stratified model (age-periods-cohort model) with 7 age classes (30-44, 45-54, 55-64, 65-69, 70-74, 75-79, and 80-89 years) was applied under the assumption that the number of deaths has an extra-Poisson variation. Results: The stratified model showed that: (1) middle-aged groups (40-64 years in men and 40-59 years in women) had higher mortality than their linear age trends; (2) young (30-44 years) and middle-aged (45-64 years) groups showed different patterns than those of the elderly (65-89 years) age groups: the two younger groups had higher nonlinear period effects than their linear trends between 1970 and 1990, and the trend of decreasing began later (in 1975 in men and 1980 in women, respectively) than it did for the elderly (1970); and (3) the nonlinear cohort effects indicated 4 patterns in each sex, and the effects increased in post-1948 cohort in men and in post-1958 cohort in women. Conclusion: Young and middle age (30-59 years) boosted the mortality, suggesting that this age range should be targeted for increased stroke prevention efforts.

Stroke mortality in Miyagi, Japan

Hypertension is a major cause in stroke mortality in Japan but is not the sole factor. This research, based on geographical comparisons between two selected towns of contrasted stroke experience, implicates a poor indoor thermal environment as having an important role, especially by sudden changes in temperature between rooms elevating blood pressure. High dietary salt is also an important contributory cause of stroke and is already the target of a public education campaign to encourage a reduced intake.

Regional differences in stroke mortality and alcohol consumption in Japan.

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