Wake-up stroke: incidence, risk factors and outcome of acute stroke during sleep in a Japanese population. Takashima Stroke Registry 1988-2003.

Characterization of the time of stroke onset has been plagued by the problem of determining the time of the onset of events that are detected when the patient awakens. Our aim was to evaluate the characteristics, risk factors and acute fatality associated with wake-up stroke. Data was obtained from Takashima Stroke Registry covering approximately 55,000 residents in central Japan. During the period 1988-2003, information about the situation at stroke onset was available for 897 cerebral infarction (CI) and 335 intracerebral hemorrhage (ICH) events. Differences in characteristics and outcome between stroke during sleep and stroke while awake were explored. Among CI and ICH cases, 9.7 and 11.9% suffered from stroke during sleep, respectively. Hypertension and experiencing a severe event were associated with stroke during sleep among CI. Smoking and experiencing a severe event were associated with stroke during sleep and a drinking history reduced the chance of stroke during sleep among ICH. Acute fatality risks did not differ between stroke during sleep and stroke while awake among both CI and ICH cases. About 1 in 10 stroke patients had an onset of stroke during sleep. Hypertensive, smoker and clinically more severely affected patients had a higher prevalence of stroke during sleep. There were no differences between the 2 groups with respect to acute-case fatality.

Short-term exposure to air pollution and incidence of stroke and acute myocardial infarction in a Japanese population.

BACKGROUND: Exposure to high levels of air pollution can increase the risk of cardiovascular events. However, there is no clear information in Japan on the effect of pollution on the incidence of stroke and acute myocardial infarction (AMI). Therefore, we investigated the effects of air pollution on the incidence of stroke and AMI in a setting where pollutant levels are rather low. METHODS: Data were obtained from the Takashima Stroke and AMI Registry, which covers a population of approximately 55,000 in Takashima County in central Japan. We applied a time-stratified, bidirectional, case-crossover design to estimate the effects of air pollutants, which included suspended particulate matter (SPM), sulfur dioxide (SO(2)), nitrogen dioxide (NO(2)) and photochemical oxidants (Ox). We used the distributed lag model to estimate the effect of pollutant exposure 0-3 days before the day of event onset and controlled for meteorological covariates in all of the models. RESULTS: There were 2,038 first-ever strokes (1,083 men, 955 women) and 429 first-ever AMI cases (281 men, 148 women) during 1988-2004. The mean pollutant levels were as follows: SPM 26.9 µg/m(3); SO(2) 3.9 ppb; NO(2) 16.0 ppb, and Ox 28.4 ppb. In single-pollutant and two-pollutant models, SO(2) was associated with the risk of cerebral hemorrhage. Other stroke subtypes and AMI were not associated with air pollutant levels. CONCLUSIONS: We observed an association between SO(2) and hemorrhagic stroke; however, we found inconclusive evidence for a short-term effect of air pollution on the incidence of other stroke types and AMI.

Ambient air pollutants and acute case-fatality of cerebro-cardiovascular events: Takashima Stroke and AMI Registry, Japan (1988-2004).

BACKGROUND: Apart from the conventional risk factors, cerebro-cardiovascular disease (CVD) are also reported to be associated with air pollution, thus lowering the level of exposure might contribute in prevention activities to reduce the associated adverse outcomes. Though few studies conducted in Japan have reported on the CVD mortality but none have explored the effect of air pollutant exposure on the acute case-fatality of CVD. We investigated the effects of air pollution exposure on acute case-fatality of stroke and acute myocardial infarction (AMI) in a setting where pollutant levels are rather low. METHODS: We leveraged the data from the Takashima Stroke and AMI Registry, which covers a population of approximately 55,000 in Takashima County located in central Japan. The study period of 6,210 days (16 years, leap years also taken into account) were divided into quartiles of daily average pollutant concentration; suspended particulate matter (SPM), sulfur dioxide (SO(2)), nitrogen dioxide (NO(2)), and photochemical oxidants (Ox). The stroke and AMI events were categorized to corresponding quartiles based on the pollution levels of the onset day. To study the effects of air pollutants, we estimated the fatality rate ratio across quartiles of the pollutants where the lowest quartile served as the reference. RESULTS: There were 307 (men: 153 and women: 154) fatal stroke cases within 28 days of onset among the 2,038 first ever stroke during 1988-2004. In the same period, there were 142 (men: 94 and women: 54) fatal AMI cases within 28 days of onset among the 429 first ever AMI events. The mean of the measured pollutant levels were as follows: SPM 26.9 µg/m(3), SO(2) 3.9 ppb, NO(2) 16.0 ppb, and Ox 28.4 ppb. Among the pollutants, higher levels of NO(2) showed increased fatality risk. In multi-pollutant model, the highest quartile of NO(2) was associated with 60% higher stroke case-fatality risk in comparison to lowest quartile of NO(2). In the fully adjusted model the fatality-rate ratio was 1.65 (95% CI 1.06-2.57). This association was more prominent among stroke subtype of cerebral infarction. Other pollutant levels did not show any association with stroke or AMI case-fatality. CONCLUSION: We observed association between NO(2) levels, an index of traffic related air pollution, with the acute case-fatality of stroke, especially cerebral infarction in our study population. Further studies are needed in different regions to determine the association between ambient air pollutants and acute cardiovascular fatalities.

Ischemic stroke subtypes in a Japanese population: Takashima Stroke Registry, 1988-2004.

BACKGROUND AND PURPOSE: Population-based information on the epidemiology of ischemic stroke (IS) subtypes is scant. In this study, we characterized IS subtypes in terms of incidence, time trend, and risk factor profiles in a community-based population. METHODS: We obtained data from the Takashima Stroke Registry on approximately 55 000 residents of Takashima County in central Japan and calculated age-adjusted stroke incidence rates for different IS subtypes. We determined the incidence time trend by calculating the average annual change across years and also compared risk factors between subtypes. RESULTS: There were 1389 first-ever ischemic strokes registered during 1988 to 2004. Lacunar infarction was the most frequent etiology (54.1%) followed by cardioembolic infarction (22.9%). Age-adjusted incidence rates for different IS subtypes were lacunar, 77.1; cardioembolic, 31.5; and nonlacunar, 29.7/10(5) person-years. The average annual change was not significant for the IS subtypes except for nonlacunar infarction, which showed a decreasing trend. Risk factor analysis showed that patients with lacunar infarctions were younger and less likely to have a history of transient ischemic attack or a drinking habit than patients with nonlacunar infarctions. CONCLUSIONS: Lacunar infarct was the most common IS subtype in our population. We found no significant change in the incidence of subtypes during the study, except a decrease in nonlacunar infarction.

Diurnal variation in onset of hemorrhagic stroke is independent of risk factor status: Takashima Stroke Registry.

BACKGROUND: We examined the circadian periodicity of hemorrhagic stroke onset to identify any existing specific pattern and its relationship with conventional stroke risk factors using 14-year stroke registration data. METHODS: Data were obtained from the Takashima Stroke Registry, which covers a stable population of approx. 55,000 in Takashima County in central Japan. Out of 499 registered first-ever hemorrhagic stroke events during 1990-2003, there were 429 (186 men, 243 women) events with classifiable onset time. Hemorrhagic stroke incidence was categorized as occurring at night (midnight to 6 a.m.), morning (6 a.m. to noon), afternoon (noon to 6 p.m.) or evening (6 p.m. to midnight). The OR (with 95% CI) of having a stroke in the morning, afternoon or evening were calculated, with night serving as reference. RESULTS: There was significant diurnal variation in hemorrhagic stroke incidence (p < 0.001). The proportion of hemorrhagic strokes was highest in the morning (36.1%, 95% CI: 31.7-40.8) and lowest in the night (11.9%, 95% CI: 9.1-15.3). An excess stroke incidence in the morning was observed in both genders, in subjects < 65 years and > or =65 years, and in both intracerebral hemorrhage and subarachnoid hemorrhage. A second surge was also observed during the later part of the day. The higher daytime risk persisted after adjusting for age, gender, and risk factors. CONCLUSION: In the examination of circadian variation of hemorrhagic stroke onset, a 2-peak temporal distribution was observed, which was independent of conventional risk factors.

Stroke case fatality shows seasonal variation regardless of risk factor status in a Japanese population: 15-year results from the Takashima Stroke Registry.

BACKGROUND: Seasonal variation in fatality caused by stroke was examined using 15 years of data from a stroke registry of a Japanese population. METHODS: Data were obtained from the Takashima Stroke Registry, which covers approximately 55,000 residents in central Japan. There were 1,650 registered cases of first-ever stroke between 1988 and 2002. 7- and 28-day fatality rates and 95% confidence intervals were calculated for winter, spring, summer and autumn. After adjusting for gender, age at onset and risk factors, the hazard ratios for fatal strokes in winter, spring and autumn were calculated, with summer serving as the reference. RESULTS: For cerebral infarction, the highest 7- and 28-day fatality rates occurred during spring and winter, where they were more than double the rate during summer. The severest strokes were also more likely to occur during winter and spring. A high spring and winter hazard ratio for 28-day mortality was present in both lacunar and nonlacunar subtypes, in both genders and in subjects < 65 and > or = 65 years of age. No apparent seasonal pattern was observed for cerebral hemorrhage or subarachnoid hemorrhage. The spring and winter excess fatality persisted even after adjusting for age, gender and risk factors. CONCLUSION: Patients who suffer an ischemic stroke during winter or spring have a poorer prognosis. Further investigation is needed to determine the factors that explain this excess risk.

The time interval window between stroke onset and hospitalization and its related factors.

OBJECTIVE: Successful acute stroke intervention depends on early hospitalization. The time interval between stroke onset to hospitalization was examined to identify the factors influencing the interval and also to determine whether treatment time window expansion will translate into more treatment. METHODS: Data was obtained from Takashima Stroke Registry covering approximately 55,000 residents in Japan. During 1988-2002, the interval between stroke onset and hospitalization was available for 1,446 registered patients (men 761, women 685). Multivariate regression analyses were performed to evaluate the factors influencing early and late admission. RESULTS: The proportions of the patients who arrived within 3 h of onset were 61.4%. Only 8.7% of the patients arrived during a 3- to 6-hour interval. A substantial proportion (29.9%) of patients arrived after 6 h. Early stroke hospitalization was significantly associated with the severity of the stroke event and time of stroke onset. CONCLUSION: Clinically more severe stroke patients were hospitalized earlier and nocturnal strokes had delayed admission. Even expanding the therapeutic time window from

Case fatality of stroke and day of the week: is the weekend effect an artifact? Takashima stroke registry, Japan (1988-2003).

BACKGROUND AND PURPOSE: For stroke admissions, the 'weekend effect' has been associated with higher stroke fatality. However, it is unclear if stroke case fatality shows this pattern if the onset day is taken into account. Day of the week variation in stroke case fatality was examined using 16-year stroke registration data. DESIGN AND METHODS: Data were obtained from Takashima Stroke Registry in central Japan. There were 1,578 registered first-ever cerebral infarction and cerebral hemorrhage stroke cases during 1988-2003. We divided the days into 2 groups: 'weekend' and 'weekdays'. The 7-day and 28-day case fatality rates and 95% confidence intervals (95% CI) were calculated by gender, age and stroke subtype. RESULTS: For all strokes, the 7-day case fatality rate based on the hospital admission day was 9.5% (95% CI: 6.8-13.1) for weekend admissions and 7.3% (95% CI: 6.0-8.9) for weekday admissions. However, case fatality rates based on the onset day were 7.2% (95% CI: 5.1-10.0) for weekend onset and 8.0% (95% CI: 6.6-9.8) for weekday onset. The 28-day case fatality rate for the weekend admission group was 14.7% (95% CI: 11.3-18.8) and for the weekday admission group it was 10.1% (95% CI: 8.5-11.9). In contrast, the 28-day case fatality rate for the weekend onset group was 11.3% (95% CI: 8.6-14.7) and for the weekday onset group it was 11.0% (95% CI: 9.3-13.0). This phenomenon was observed mainly for cerebral infarction and to some extent for cerebral hemorrhage. CONCLUSION: Stroke fatality rates based on the day of admission were higher during the weekend than weekdays, although the difference did not reach statistical significance. However, this trend disappeared when the fatality rate was based on the day of onset.

Circumstances, activities, and events precipitating aneurysmal subarachnoid hemorrhage.

Medical records of 513 patients with aneurysmal subarachnoid hemorrhage were reviewed to analyze the factors precipitating aneurysmal rupture. There was no seasonal difference in incidence. A significantly higher incidence was observed during 6:00 AM to 9:00 AM and 6:00 PM to 9:00 PM when engaging in daily routines such as defecation/micturition, brushing teeth/washing face/dressing, eating/drinking, and taking a bath. These activities are associated with a Valsalva maneuver that results in sudden pressure changes across the aneurysmal wall precipitating aneurysmal rupture. Aneurysmal rupture occurred most frequently during talking, chatting, watching television, or staying home without any strenuous physical activity. Considering the time spent, the highest incidence rate was found during defecation/micturition. There was no significant difference between men and women or between younger and older age groups regarding activities or events preceding aneurysmal rupture. Hypertension was the most common pre-existing medical problem. The main results are the same as those of the previous study except for aging of the patients.

Acute case-fatality rates of stroke and acute myocardial infarction in a Japanese population: Takashima stroke and AMI registry, 1989-2005.

BACKGROUND: Few comprehensive stroke and acute myocardial infarction registries of long duration exist in Japan to illustrate trends in acute case-fatality of stroke and acute myocardial infarction with greater precision. We examined 17-year case-fatality rates of stroke and acute myocardial infarction using an entire community-monitoring registration system to investigate trends in these rates over time in a Japanese population. METHODS: Data were obtained from the Takashima Stroke and AMI Registry covering a stable population of approximately 55 000 residents of Takashima County in central Japan. We divided the total observation period of 17 years into four periods, 1989-1992, 1993-1996, 1997-2000, and 2001-2005. We calculated gender, age-specific and age-adjusted acute case-fatality rates (%) of stroke and acute myocardial infarction across these four periods. RESULTS: During the study period of 1989-2005, there were 341 fatal cases within 28 days of onset among 2239 first-ever stroke events and 163 fatal cases among 433 first-ever acute myocardial infarction events. The age-adjusted acute case-fatality rate of stroke was 14·9% in men and 15·7% in women. The age-adjusted acute case-fatality rate of acute myocardial infarction was 34·3% in men and 43·3% in women. The age-adjusted acute case-fatality rates of stroke and acute myocardial infarction showed insignificant differences across the four time periods. The average annual change in the acute case-fatality rate of stroke (-0·2%; 95% CI: -2·4-2·1) and acute myocardial infarction (2·7%; 95% CI: -0·7-6·1) did not change significantly across the study years. CONCLUSIONS: The acute case-fatality rates of stroke and acute myocardial infarction have remained stable from 1989 to 2005 in a rural and semi-urban Japanese population.

Circaseptan variation in case-fatality rate for patients with acute subarachnoid hemorrhage (Takashima Stroke Registry 1988-2003).

We explored the circaseptan variation in 28-day case-fatalities for patients with subarachnoid hemorrhage (SAH) across days of the week. Data were obtained from the Takashima Stroke Registry, which covers approximately 50000 residents of central Japan. There were 169 first-ever SAH cases registered during the period 1988-2003 (68 in males, 101 in females). We divided the SAH cases into two groups according to the day on which the SAH occurred: "weekend" and "weekday". The 28-day case-fatality rate and 95% confidence interval (CI) were calculated. Multiple logistic regression analysis was used to calculate the adjusted odds ratio (95% CI) for weekday fatalities by entering all relevant patient-level variables into the model. The 28-day case-fatality rate for SAH was higher on weekdays (51.7%) than on weekends (32.6%; odds ratio 2.19; 95% CI: 1.10-4.49). The differences in fatality rate persisted after adjustment for age, sex, severity, family history of stroke and patient history of hypertension, diabetes mellitus, dyslipidemia, drinking and smoking. We observed a circaseptan variation in fatalities from SAH, with higher fatality rates during weekdays in our study population.

Growth pattern changes of meningiomas: long-term analysis.

OBJECTIVE: Although tumors are generally expected to grow exponentially, it is not known whether meningiomas retain a constant growth rate or not because of the lack of long-term follow-up. We analyzed the long-term growth pattern of meningiomas. METHODS: Twenty patients with a total of 31 meningiomas were radiologically followed for 4.1 to 18.3 years (median, 10.1 yr). Seven patients (including two neurofibromatosis cases) had incidental tumors. Another 13 patients with symptomatic tumors were followed after surgery. Their volumes were measured, and their time-volume curves were plotted. RESULTS: The growth curves of four atypical meningiomas fitted better to an exponential curve (R > 0.95). Two calcified tumors did not grow. Although the other benign tumors grew exponentially or linearly, their tumor volume doubling times in the initial phase were shorter than those in the later phase in most cases. Meningiomas without calcification tended to grow exponentially, whereas those with calcification were likely to reveal a linear growth pattern (P = 0.002, chi2 test). This was supported by the observation that in two patients, the tumor growth pattern changed from exponential to linear and from linear to no growth with progression of calcification. CONCLUSION: Three growth patterns of meningiomas were demonstrated. Atypical meningiomas grew exponentially. Conversely, benign meningiomas revealed exponential, linear, or no growth. The growth pattern of the latter may change with the appearance of calcification.