Cerebrovascular disease: frequency and population selectivity in an upper midwestern community

Personalized Spiking Neural Network Models of Clinical and Environmental Factors to Predict Stroke

The high incidence of stroke occurrence necessitates the understanding of its causes and possible ways for early prediction and prevention. In this respect, statistical methods offer the “big picture,” but they have a weak predictive ability at an individual level. This research proposes a new personalized modeling method based on computational spiking neural networks (SNN) for the identification of causal associations between clinical and environmental time series data that can be used to predict individual stroke events. The method is tested on 804 stroke patients. Given a clinical data set of patients who experienced a stroke in the past and the corresponding environmental time-series data for a selected time-window before the stroke event, the method identifies the clusters of individuals with a high risk for stroke under similar conditions. The methodology involves a pipeline of processes when creating a personalized model for an individual $$x$$ x : (1) selecting a group of individuals $$Gx$$ Gx with similar personal records to $$x$$ x ; (2) training a personalized SNN $$x$$ x model of several days of environmental data related to the $$Gx$$ Gx group to predict the risk of stroke for $$x$$ x at least one day earlier; (3) model interpretability through 3D visualization; (4) discovery of personalized predictive markers. The results are twofold, first proposing a new computational methodology and second presenting new findings. It is found that certain environmental factors, such as SO2, PM10, CO, and PM2.5, increase the risk of stroke if an individual $$x$$ x belongs to a certain cluster of people, characterized by a combination of family history of stroke and diabetes, overweight, vascular/heart disease, age, and other. For the used population data, the proposed method can predict accurately individual risk of stroke before the day of the stroke. The paper presents a new methodology for personalized machine learning methods to define subgroups of the population with a high risk of stroke and to predict early individual risk of the stroke event. This makes the proposed cognitive computation method useful to reduce morbidity and mortality in society. The method is broadly applicable for predicting individual risk of other diseases and mental health conditions.

The effect characteristics of temperature on stroke mortality in Inner Mongolia and globally

The current study investigated the correlation between stroke mortality and temperature. Monthly and seasonal variations in stroke mortality were plotted and daily stroke-related deaths were calculated. The lag times were calculated using the time series analysis. The correlation between stroke incidence and the diurnal temperature range (DTR) was analyzed using case-crossover analysis. Global stroke mortality was described in five latitudes. In the eastern region of Inner Mongolia, the stroke mortality was 174.18/105, about twice of that of the midwestern regions (87.07/105), and temperature was negatively correlated with stroke mortality. Mortality peaked in the winter and troughed in the summer (χ² = 13.634, P < 0.001). The days in which stroke-related deaths were greater than ten occurred between late October and early April. The effect of temperature on stroke incidence occurred during a lag time of 1 (P = 0.024) or 2 months (P = 0.039). A DTR over 13 °C was positively correlated (r = 0.95, P = 0.004) with stroke with a lag time of 1 day. The effect of temperature on stroke was shown to be the same for various populations. As the latitude increases, stroke mortality also increases with latitudes > 40°; the highest mortality was 188.05/105 at the highest latitude. Only in relatively cold regions as the temperature decreases does stroke mortality increase for various populations. Differences in the time lag as well as in the DTR lag and DTR critical point vary for both the temperature and region.

[Impact of seasons, years El Nino/La Nina and rainfalls on stroke-related morbidity and mortality in Kinshasa]

INTRODUCTION

The significant impact of seasonality and climate change on stroke-related morbidity and mortality is well established, however, some findings on this issue are conflicting. The objective was to determine the impact of gender, age, season, year of admission, temperature, rainfall and El Nino phenomenon on ischemic and hemorrhagic strokes and fatal cases of stroke.

METHODS

The study was carried out at the teaching hospital of Kinshasa, DRC, between January 1998 and December 2004. Rainy and dry seasons, elevated temperatures, indices of rainfalls El Nino years 1998, 2002 and 2004, but La Nina years 1999-2000 and neutral/normal years 2001 and 2003 were defined.

RESULTS

Among 470 incident strokes, 34.5% of victims (n=162) died. Traditional seasons (small dry season, small rainy season, great dry season, great rainy season) and temperatures did not significantly (P>0.005) impact on stroke incidence. However, there was a positive association between the decrease in rainfall, El Nino, and incident ischemic strokes, but a significant positive association between the increase in rainfall, La Nina, and incident hemorrhagic strokes. Using logistic regression analysis, age ≥ 60 years (OR: 1.7, 95% CI: 1.2-2.5; P=0.018) and El Nino years (OR: 2, 95% CI: 1.2-3.3; P=0.009) were identified as the independent predictors of fatal strokes.

CONCLUSION

Early warning systems should be developed to predict the impact of seasons and climate variability on stroke morbidity and mortality.

Gender-related protection from or vulnerability to severe CNS diseases: gonado-structural and/or gonado-activational? A meta-analysis of relevant epidemiological studies

BACKGROUND

A vast scientific literature has dealt with gender-specific risk for brain disorder. That field is evolving toward a consensus to the effect that the estrogen hormone family is outstandingly and uniquely neuroprotective. However, the epidemiology relevant to this general outlook remains piecemeal.

METHOD

The present investigation strategically formats the relevant epidemiological findings around the world in order to quantitatively meta-analyze gender ratio of risk for a variety of relevant severe central nervous system (CNS) diseases at all three gonadal stages of the life cycle, pre pubertal, post adolescent/pre menopausal, and post menopausal.

RESULTS

The data quantitatively establish that (1) no single epidemiological study should be cited as evidence of gender-specific neuroprotection against the most common severe CNS diseases because the gender-specific risk ratios are contradictory from one study to the other; (2) risk for severe CNS disease is indeed significantly gender-specific, but either gender can be protected: it depends on the disease, not at all on the age bracket.

CONCLUSION

Our assay of gender-specific risk for severe brain disease around the world has not been able to support the idea according to which any one gender-prevalent gonadal steroid hormone dominates as a neuroprotective agent at natural concentrations.

Breaking heart: chronobiologic insights into takotsubo cardiomyopathy

A considerable amount of evidence has shown that the major acute cardiovascular diseases, ie, myocardial infarction, sudden cardiac death, stroke, pulmonary embolism, and rupture or dissection of aortic aneurysms do not occur randomly in time, but exhibit specific temporal patterns in their onset, according to time of day, month or season, and day of the week. This contributes to the definition of "chronorisk", where several factors, not harmful if taken alone, are capable of triggering unfavorable events when presenting all together within the same temporal window. This article reviews the actual knowledge about time of onset of takotsubo cardiomyopathy.

Environmental factors and stroke: A selective review

Despite numerous prior stroke risk factor investigations, much remains unknown about the effect of environmental factor changes on stroke incidence and mortality rates. Yet these data might be important for defining a number of measures to prevent stroke and for developing a greater understanding of the origin and incidence trends of stroke in different regions and populations. In this paper we review the current state of knowledge about certain environmental stroke risk factors.

Temporal Patterns of Hospital Admissions for Transient Ischemic Attack: A Retrospective Population-based Study in the Emilia-Romagna Region of Italy

Acute cerebrovascular events are not randomly distributed over time but show specific temporal patterns of occurrence. However, most studies focused stroke and little is known about transient ischemic attack. This study aimed to explore the existence of a temporal pattern of transient ischemic attack and the possible influence by the most common risk factors. The analysis included all hospital admissions with the ICD9-CM code for TIA, recorded in the database of the Emilia Romagna region of Italy (1998-2006; n = 43642, mean age 76.8 ± 11.5 years, 45.5% males). Transient ischemic attack was most frequent in autumn and winter and less common in spring and summer (P < 0.0001), with the highest number of cases in October and the lowest in February, and also most frequent on Monday (P < 0.0001). This study shows a seasonal and weekly pattern in occurrence of transient ischemic attack, independent of sex and the presence of the most common risk factors.

Seasonal Patterns of Incidence and Case Fatality of Stroke in Malmö, Sweden: The STROMA Study

BACKGROUND

Studies on the temporal variation in stroke incidence have reported inconsistent results. Few have studied the temporal variations in case fatality. No study on incidence and case fatality of stroke by season in Sweden has been found. This study explores the weekly, monthly and seasonal variations in incidence and 28-day case fatality of stroke.

METHODS

A total of 7,129 patients with first-ever stroke during the period 1989-1999 were retrieved from the Stroke Register of Malmo, Sweden. chi(2) test was performed to test the seasonal differences and Poisson regression analysis was used to calculate the case fatality ratios adjusted for sex and age.

RESULTS

The stroke cases were on the whole randomly distributed over the study period of 4,017 days. Incidence of all types of stroke, intracerebral hemorrhage and subarachnoid hemorrhage showed no variation by season, month or weekday, but incidence of cerebral infarction for the total population was higher in autumn and winter. Twenty-eight-day case fatality (930 fatal events, 13%) clustered significantly over the study period. Winter emerged as the peak season among men (12.5%), women (17.2%) and total population (15.1%). No consistent variation of incidence and case fatality of stroke by month or weekday was found.

CONCLUSION

Case fatality after stroke demonstrates a seasonal variation with a peak in winter. Incidence of stroke showed no consistent association with season, month or weekday.

Variation in ischemic stroke frequency in Japan by season and by other variables

BACKGROUND AND PURPOSE

It is unclear whether acute ischemic stroke exhibits a seasonal pattern in Japan. The aim of the present study was to elucidate seasonal differences in acute ischemic stroke.

METHODS

Our study enrolled 12,660 patients with ischemic stroke (7943 men, 4717 women; mean age, 70.1 years, S.D. 11.5; median 70; range 18-107). We divided the year into four parts: spring (March-May); summer (June-August); fall (September-November); and winter (December-February). Time of stroke onset was divided into three subgroups: daytime (08:00-16:00), evening (16:00-24:00), and night (24:00-08:00). We examined the association between clinical characteristics, season, and time of stroke onset.

RESULTS

Stroke occurred least frequently in spring (22.9%), followed by winter (25.3%), fall (25.8%), and summer (26.0%) (P<0.001). No differences in age, National Institutes of Health Stroke Scale (NIHSS) score, modified Rankin Scale (m-RS) score, history of stroke/transient ischemic attack (TIA), or risk factors for stroke were observed among the four seasons. Stroke in men (63.8% vs. 62.4%; P<0.01), lacunar stroke (LS) (41.2% vs. 39.4%, P<0.01), atherothrombotic stroke (ATS) (34.0% vs. 32.3%; P<0.01), and nighttime stroke (26.5% vs. 24.8%; P<0.05) were observed more frequently in summer compared to other seasons. This contrasts with the findings for stroke in women (39.0% vs. 36.7%; P<0.05), cardioembolic stroke (CES) (23.4% vs. 20.6%; P<0.05), and daytime stroke (47.4% vs. 45.0%; P<0.05), which were more frequent in winter.

CONCLUSIONS

Acute ischemic stroke displays seasonal characteristics according to gender, stroke subtype, and time of stroke onset. These results may have important clinical implications in ischemic stroke prevention.

Variation saisonnière des accidents vasculaires cérébraux et influence des conditions météorologiques

The aim of this paper was to study the seasonal and Monthly distribution of different subtypes of strokes, and also the influence of the most usual meteorological factors on their incidence. The study, based on the population-based data of the Dijon register of stroke (France), involved 3287 patients with a cerebrovascular event during the Years 1985-1998. The seasonal distribution pointed out a summer decrease for all stroke subtypes. The cerebrovascular risk was the highest in autumn for small artery atheroma infarcts and for cerebral infarcts and, among these later, for cardioembolic infarcts and large artery atheroma infarcts, as well as for subarachnoid hemorrhages and for the total number of strokes. It was followed by spring (total number of strokes, small artery atheroma infarcts, cerebral infarcts) and/or winter (subarachnoid hemorrhages, cerebral infarcts, cardioembolic infarcts and large artery atheroma infarcts). For intracerebral hemorrhages, the risk peaked in spring and secondly in autumn. But the difference from one season to another was significant only for total number of strokes, cerebral infarcts and, among the later, for cardioembolic infarcts and large artery atheroma infarcts. As regards the Monthly distribution, the difference between Months was significant only for the total number of strokes and cerebral infarcts, with a minimum from July to September and a maximum in October for the later. Correlations with meteorological data were found for the total number of strokes, cerebral infarcts, cardioembolic infarcts, large artery atheroma infarcts and small artery atheroma infarcts. They showed an influence of temperature and relative humidity of the day of stroke or of the one to five days before. Correlations with wind speed, duration of sunshine or snow, even if less frequent, could also be found. Such results sometimes differ from those of some earlier studies, for which the climate and the risk factors were not the same, showing that regional epidemiological studies are necessary in order to determine the relations between seasons, meteorological factors and strokes.

Estimate of the maximum time interval between formation of cerebral aneurysm and rupture

The recent publication of the results of the international study on unruptured intracranial aneurysms highlighted a paradox: there do not seem to be enough unruptured aneurysms in the population to account for the observed incidence of subarachnoid haemorrhage. Some authors have suggested that the answer to this paradox is that most aneurysms that bleed do so shortly after formation. This would mean that the bulk of subarachnoid haemorrhages come from recently formed rather than long standing aneurysms. This paradox and proposed answer are examined. The available statistics on the incidence of subarachnoid haemorrhage, the prevalence of unruptured aneurysms, and the risk of bleeding from unruptured aneurysms are used to place a maximum on the time interval between aneurysm formation and rupture. For aneurysms less than 10 mm in diameter in persons with no history of subarachnoid haemorrhage, an estimate of less than 42 weeks was made. The null hypothesis that such aneurysms pose a constant risk with time is rejected with p <10(-9). In larger aneurysms the risk seems to be constant with time.

Intracerebral hemorrhage

Intracerebral hemorrhage (ICH) represents a significant fraction of all strokes and causes a disproportionate amount of stroke related morbidity and mortality, especially in young blacks. While diagnosis of this disorder has greatly improved in the CT era, morbidity and mortality remain essentially unchanged. Not one currently utilized therapeutic modality has been clearly associated with a beneficial effect on long term outcome in small prospective randomized treatment trials for ICH. In spite of the lack of scientific data regarding therapy, patients often require aggressive medical and surgical intervention because of the life-threatening presentation of many patients. Recent clinical and experimental ICH research has identified a number of potentially effective new therapeutic strategies, and time to treatment is likely to be very important as it is for ischemic stroke. Large prospective, randomized, placebo controlled trials to examine the judicious application of current therapeutic modalities, and to investigate the potential benefit of proposed new treatment modalities, are long overdue.

Basic characteristics of hospital stroke services in Eastern Hungary

Stroke mortality is extremely high in Central-Eastern European countries. We report basic characteristics of a stroke unit in Eastern Hungary, including age and sex distribution; the proportion of transient ischemic attacks (TIA), ischemic and hemorrhagic strokes; case fatality; application of diagnostic methods; and length of stay for all patients treated with acute cerebrovascular disease over a 12-month period. Records of all patients with acute cerebrovascular disease (n = 522) discharged in 1995 from a stroke unit with a well defined catchment area of 220,000 inhabitants in Eastern Hungary were retrospectively analyzed. Case fatality was 18.6% for all patients and 21.1% after excluding cases with TIA. Computer tomography, duplex carotid ultrasound, cerebrospinal fluid examination and electroencephalography were performed in 79%, 77%, 7% and 2% of the patients, respectively. The database of the university hospital with the same catchment area was electronically searched for patients who were discharged with the diagnosis of stroke from the three departments of internal medicine. Stroke mortality data of the catchment area based on death certificates was obtained from the Central Statistical Bureau. Two hundred twenty-eight stroke deaths were reported in the catchment area in 1995. In the same period 97 stroke deaths occurred at the stroke unit and 76 at the departments of internal medicine. If we aim to treat all patients with acute stroke at the stroke unit, with the present stroke incidence and duration of hospital stay the current capacity of the stroke unit (1 bed per 10.000 inhabitants) should be doubled.

Chronobiological patterns of onset of acute cerebrovascular diseases

There is a considerable amount of data indicating that several major unfavorable cerebrovascular events are not randomly distributed over time, but show a peculiar distribution along the day, the week, and the months of the year. The authors review the available evidence on the chronobiological (circadian, weekly, and seasonal) patterns of onset of acute cerebrovascular diseases and variations in their possible triggering mechanisms. The existence of a peculiar chronobiological pattern in the onset of acute cerebrovascular disease, characterized by both circadian (morning and evening occurrence), circaseptan (last and first days of the week), and circannual (especially in winter) is confirmed, although differences depending on biological (gender, age), pathological (diabetes, hypertension, smoke, alcohol), cultural, social, and environmental factors exist. A deeper knowledge of the underlying pathophysiologic mechanisms could provide more effective insights for both preventive strategies and optimization of therapeutic approach.

Seasonal fluctuation in the incidence of intracranial aneurysm rupture and its relationship to changing climatic conditions

Seasonal and climatic variations have been linked to the occurrence of some types of cerebrovascular disease; however, the conditions that lead to intracranial aneurysm rupture are not known. The purpose of the present study was to determine whether seasonal and climatic conditions are related to intracranial aneurysm rupture. Data provided by the Connecticut Health Information Management and Exchange were analyzed for all patients with a primary diagnosis of aneurysmal subarachnoid hemorrhage (SAH) for the fiscal years 1981, 1983, 1985, 1987, 1988, and 1989. Patient records were correlated with climatic conditions for the years 1981 to 1989 obtained from the National Climatic Data Center, National Oceanic and Atmospheric Administration, National Environmental Satellite Data, and Information Service. During the time periods studied, 1487 patients with a primary diagnosis of aneurysmal SAH were treated by reporting hospitals. Seasonal variation in the incidence of aneurysmal SAH and admission clustering were observed but differed significantly between men and women. Men showed a single large peak in late fall (Roger's r = 11.5, p < 0.005), whereas women had an annual peak occurring in late spring (Roger's r = 10.3, p < 0.01). Substantial climatic change occurred during the 72 hours prior to 10 of the 14 clusters of men who were admitted (p < 0.01, Yates' corrected chi-square 7.33, df = 1). In contrast, clusters of women admitted were not related to preceding climatic change (p > 0.25, Yates' corrected chi-square 0.06, df = 1). Hospital admissions for aneurysmal SAH display seasonal fluctuation, with women showing a different seasonal pattern from men. Changing climatic conditions precede aneurysm rupture in men but not in women, which suggests that weather is causally related to aneurysm rupture in men, and that factors that lead to aneurysm rupture in women may be different from those in men. These data do not explain why weather fronts or gradients are associated with aneurysm rupture in men.

Thrombotic occlusion of the middle cerebral artery

BACKGROUND AND PURPOSE

Epidemiological study of middle cerebral artery occlusion is important because the indication for extracranial-intracranial arterial bypass remains in dispute. To help clarify this issue, we investigated the prognosis of thrombotic middle cerebral artery occlusion in Japanese patients.

METHODS

We studied 40 patients with thrombotic middle cerebral artery occlusion who were selected on the basis of clinical features, computed tomographic findings, and angiographic findings. Patients with causes of embolism (i.e., cardiomyopathy, valvular heart disease, cardiac arrhythmia, and carotid ulceration) were excluded. The 40 patients were classified into three groups according to the site of middle cerebral artery occlusion: there were 13 patients with occlusion of the proximal portion of the M1 segment, 13 with distal M1 segment occlusion, and 14 with occlusion of the M2 segment.

RESULTS

Good collateral circulation was associated with improved outcomes both clinically and by computed tomography in patients with occlusion of the proximal and distal portions of the M1 segment but not in those with M2 occlusion.

CONCLUSIONS

It is reasonable to assume that not only collateral circulation but also the site of occlusion plays an important role in the outcome of middle cerebral artery occlusion. Our finding that good collateral circulation improves the outcome for thrombotic occlusion of the proximal and distal M1 segments supports the possible benefits of such surgery.

Seasonal variation of cerebrovascular diseases

The seasonal variation in all admissions of all types of cerebrovascular disease within the West Midlands Region was examined between the years 1973-1980. There was a fluctuation for both sexes with a peak in winter, between the months of October and April; a trough was observed in late summer, in July and August. Multivariate analysis of the meteorological factors showed an association between hours of sunshine and intracerebral haemorrhage. The meterological variables were strongly correlated with each other making the selection of the most predictable variable to stroke difficult.

Seasonal variation in stroke incidence in Hisayama, Japan

We investigated seasonal variation in the incidence of cerebral stroke among the general population aged greater than or equal to 40 years in November of 1961 in Hisayama, Japan. During the 24-year follow-up period, 311 cases of cerebrovascular diseases occurred. The date or month of onset was determined in 308 cases, of which 51 were classified as intracerebral hemorrhage, 223 as cerebral infarction, and 27 as subarachnoid hemorrhage. We observed a significant seasonality in the incidence of all stroke (p less than 0.01), of intracerebral hemorrhage (p less than 0.05), and of cerebral infarction (p less than 0.01), whereas subarachnoid hemorrhage had no significant seasonal pattern. Subjects less than 64 years of age showed a significant seasonal variation in the incidence of both intracerebral hemorrhage (p less than 0.05) and cerebral infarction (p less than 0.01). A significant seasonal pattern for the incidence of intracerebral hemorrhage was also noted among persons with hypertension (p less than 0.05) or a high serum cholesterol level (p less than 0.05), whereas such a pattern for cerebral infarction was documented among normotensive persons (p less than 0.05) and those with a low serum cholesterol level (p less than 0.01). In addition, the incidences of intracerebral hemorrhage and cerebral infarction were negatively correlated with mean ambient temperature (p less than 0.01 and p less than 0.05, respectively), and all stroke and intracerebral hemorrhage in men were significantly related to intradiurnal temperature change (p less than 0.05 and p less than 0.01, respectively). The significance of the seasonal occurrence of stroke is discussed in relation to relevant risk factors.

Community hospital-based stroke programs in North Carolina, Oregon, and New York. IV. Stroke diagnosis and its relation to demographics, risk factors, and clinical status after stroke

The use of diagnostic tests, the accuracy of stroke type diagnosis, and their relationship to outcome are important from the standpoint of patient management and health care costs. To address this issue, we examined the differences between stroke types in terms of demographics, risk factors, diagnostic tests, and clinical outcome in the 4,129 patients who comprise the Community Hospital-Based Stroke Program. Previous transient ischemic attacks were equally frequent among patients with embolic and those with thrombotic stroke. For all stroke types, previous stroke was as frequent as previous transient ischemic attacks. Hypertension and cardiac disease were the most common risk factors, but 10% of all stroke patients had no recognized risk factors. Intracerebral hemorrhage was most often associated with death (45%). There was a strong direct relation between in-hospital mortality and a decreased level of consciousness at admission. Overall, 30% of patients did not receive a specific stroke type diagnosis; these patients were elderly, usually nonwhite, and often had an altered level of consciousness at admission but had a risk factor profile similar to that of patients who received a specific stroke type diagnosis. In summary, our findings suggest the continued need for physician education about and refinement of stroke type diagnosis.

Infarcts of undetermined cause: the NINCDS Stroke Data Bank

In a prospective study of 1,805 hospitalized patients in the Stroke Data Bank of the National Institute of Neurological and Communicative Disorders and Stroke, the 1,273 with infarction were classified into diagnostic subtypes. Diagnosis was based on the clinical history, examination, and laboratory tests including computed tomography, noninvasive vascular imaging, and where safe and relevant, angiography. Five hundred and eight cases (fully 40%) were labeled as infarcts of undetermined cause (IUC), of which 138 (27%) were evaluated with both computed tomography and angiography. The clinical syndrome and computed tomographic and angiographic findings in 91 (65.9%) of these 138 IUC cases were clearly not attributable to large-artery thrombosis and could permit reclassification of the infarct as due to some form of embolism. Failure to define a source of embolus kept them in the category of IUC. Thirty-one cases (22.5%) could be reclassified as due to stenosis or thrombosis of a large artery, and 16 (11.6%) as lacunar infarction. To determine if those selected for angiography among the IUC patients differed from those with other final diagnoses, a stepwise multiple logistic model was used. The most important characteristics were young age, presence of a superficial infarct, prior transient ischemic attack, low weakness score, and presentation with a nonlacunar syndrome. The results of the model suggest that angiography use was determined by clinical characteristics uniformly across centers and not by final diagnosis. Continued use of the category IUC may help clarify risk factors and stroke subtypes, allow new mechanisms of ischemic stroke to be uncovered, and prevent classification categories of stroke used in clinical trials from becoming too broad.

Epidemiology of stroke in Lund-Orup, Sweden, 1983-85. Incidence of first stroke and age-related changes in subtypes

The incidence of stroke in the hospital district of Lund-Orup (total population 200,191), the local uptake area of the University Hospital, Lund, was studied. Between January 1, 1983 and December 31, 1985, there were 1054 cases of first stroke. Age adjusted (to Swedish Dec 1983 population) incidence rates were 221.2 for males, 195.8 for females, and 208.3 for total population (per 100,000 and year). Case-fatality ratio by 30 days was 17.5%. Atherothrombotic infarction was the most common subtype (58.4%), followed in frequency by cardiac embolism (30.6%), intracerebral hemorrhage (8.3%) and subarachnoid hemorrhage (2.7%). The most important change in the distribution of subtypes with age was an increase in the proportion of cardiac embolism from 13% in the youngest to 44% in the oldest age groups. The present study underscores the importance of careful determination of subtypes of stroke in future epidemiological studies.

The Lausanne Stroke Registry: analysis of 1,000 consecutive patients with first stroke

We present epidemiologic, etiologic, and clinical data for 1,000 consecutive patients with a first stroke (cerebral infarction or hemorrhage) admitted to the Centre Hospitalier Universitaire Vaudois since 1982. The patients were evaluated using a standard protocol of tests (computed tomography, Doppler ultrasonography, and electrocardiography in all patients, as well as angiography and specific cardiac investigations in selected patients). Each case was coded prospectively into a computerized registry. We believe that the Lausanne Stroke Registry is the first registry with complete computed tomography and Doppler ultrasonography data on all patients, which allows correlation between clinical findings, presumed etiology, and stroke location. Although the Lausanne Stroke Registry is not population-based, it gives a good estimate of the stroke-related problems in patients admitted to a primary-care center since our hospital is the sole acute-care facility for stroke in the Lausanne area.

Incidence of stroke in young adults in Florence, Italy

A population-based study specifically addressing stroke in young adults (aged 15-44 years) was conducted in Florence, Italy, from 1983 to 1985. We identified 47 cases of first stroke by means of a daily check of the medical facilities of the city and nearby towns and a review of death certificates. Patients were assessed by a neurologist shortly after the onset of the stroke, and computed tomography or autopsy was performed in 96%. The average annual incidence rate for all stroke (cases per 100,000 population per year) was 9.0 (95% confidence interval 5.8-13.4) for males and 8.7 (95% confidence interval 5.5-13.0) for females. The average annual incidence rates for the pathologic types of stroke were 3.4 for cerebral infarction, 3.2 for subarachnoid hemorrhage, and 1.9 for intracerebral hemorrhage. The case-fatality ratio was 23.4% at 1 month. Among patients with ischemic strokes, atherosclerosis and cardiac disease accounted for 50% of the cases. Based on angiography or autopsy findings, aneurysm or arteriovenous malformation were demonstrated in 88% of the patients with subarachnoid hemorrhage. In 50% of the patients with intracerebral hemorrhage, no cause of bleeding was detected. Our study may supply information about stroke pathologic types in an unselected series of young adults.

Wind-chill and the seasonal variation of cerebrovascular disease

The hospital admission rates for patients with specific types of stroke were examined for seasonal variation and correlation with meteorological factors. A seasonal variation in admission rates was found for subarachnoid haemorrhage, thrombo-embolic brain infarction and ill-defined cerebrovascular disease. Overall this seasonality was more strongly associated with the computed chilling effect of the atmosphere than with changes in temperature, humidity or wind speed alone. No seasonal variation was observed for admission rates of intracerebral haemorrhage, transient ischaemic attack or occlusion of precerebral arteries. Intracerebral haemorrhage admission rates exhibited a decrease with time. This evidence suggests that seasonal variation in admission rates exists only for certain pathological types of stroke and this is strongly associated with changes in the chilling effect of the atmosphere.

Stroke in the Lehigh Valley: seasonal variation in incidence rates

We investigated the seasonal pattern of stroke using the Lehigh Valley Stroke Register. This register includes all patients hospitalized with stroke or transient ischemic attack (TIA) from among the 600,000 Lehigh Valley residents. Meterological data were obtained from the National Oceanic and Atmospheric Administration. The study, which uses 18 months of data, included 1,944 cases. Using single harmonic regression analysis, the seasonal pattern of TIA and infarction, but not hemorrhage, fit a sine-cosine wavefunction with a 12-month period (R2 = 41% and 36%, respectively). For infarction, the strongest seasonal pattern was exhibited for women of all ages and for both sexes in the age groups 65-74 and 75-84, but only the sine component was significant. The peak months for TIA were June-August, while the peak months for infarcts were February-April. Correlations between ambient temperature and each type of stroke were computed. A significant positive correlation for TIA was found (r = 0.57, p = 0.01). After adjusting for a 2-month lag between the low for infarction and the peak for temperature, a significant negative correlation was found (r = -0.64, p = 0.01). No significant correlation was found for hemorrhage. Possible reasons for the opposite relations of TIA and infarct are discussed.

Community Hospital-based Stroke Programs: North Carolina, Oregon, and New York. I: Goals, objectives, and data collection procedures

In order to assess the impact of variations in stroke care on outcomes, and to make geographic comparisons, the three Community Hospital-Based Stroke Programs in North Carolina, Oregon, and New York, aggregated their data on 4,132 hospitalized stroke patients. Complete demographic data or "Major Profile" were obtained on 2,390 (57.8%) of the 4,132 stroke patients. This includes those patients on whom informed patient and physician consents were obtained during the hospitalization. Of the major profile patients, 1,490 (62.3%) were followed for periods up to one year, 502 (21.0%) were lost to followup and 398 (16.6%) died within the one year followup period. Incomplete demographic data or "Minor Profile" were observed on 1,742 (42.1%) of the 4,132 patients. Minor profile includes those who died before comprehensive interviews were completed or those for whom informed consent for an interview could not be obtained. Of the minor profile group, 813 (46.7%) died in hospital, and 929 (53.3%) were alive when discharged from the hospital. This paper, which describes the programs, data collection procedures, and study cases, also highlights specific issues on stroke diagnosis, risk factors associated with stroke, and the influence of interventions on stroke outcomes. We conclude that: 1) the merging of data on hospitalized stroke cases from rural and urban hospitals in geographically distinct regions can be used in the study of stroke diagnosis, the use of diagnostic tests, and the effect of interventions on stroke outcomes; and 2) these data are consistent with the hypothesis that part of the national decline in mortality from stroke is due to a decline in stroke severity.

Cause of cerebral infarction in the carotid territory. Its relation to the size and the location of the infarct and to the underlying vascular lesion

Seventy-three patients with acute nonhemorrhagic stroke in the carotid territory were investigated for the cause of the stroke: middle cerebral artery (MCA) occlusion/stenosis or internal carotid artery (ICA) occlusion/stenosis; embolus from the heart and extra-cranial arteries or thrombosis. The study is prospective and consecutive comprising stroke patients below the age of 75 years, admitted in the acute state i.e. within 3 days after stroke onset. Excluded were patients with intracerebral hematoma, subarachnoid hemorrhage, vertebrobasilar stroke and patients in whom another severe disease was present. Cerebral angiography and CT-scan were performed in all patients within one and two days after admission. CT-scan was repeated 2 weeks and 6 months later. Forty percent had MCA occlusion, none had MCA stenosis, 12% had ICA occlusion, 14% had severe ICA stenosis (half of these were associated with MCA occlusion) and 41% were without significant MCA/ICA lesions. Twenty-seven percent had large infarcts with a diameter greater than 3 cm; 34% had medium-sized infarcts with a diameter between 3 and 1.5 cm; 21% had small infarcts with a diameter less than 1.5 cm; 18% had no identifiable infarct on CT-scan. MCA occlusion was responsible for 62% of the large or medium-sized infarcts. ICA occlusion or severe ICA stenosis were responsible for only 27% of the large or medium-sized infarcts. Only 11% of the patients with small or no infarct on CT-scan had significant MCA/ICA lesion.(ABSTRACT TRUNCATED AT 250 WORDS)

A collaborative study of stroke incidence in Japan: 1975-1979

A Japan Collaborative Study of Stroke covering 20 regional and occupational population groups was conducted with the support of the Ministry of Health and Welfare. In this study 17,423 males and 16,856 females, aged 40 to 69, were followed up prospectively from 1975 to 1979. The average annual incidence of all types of stroke was 3.94 for men and 2.52 for women per 1,000 population. The incidence of cerebral hemorrhage for men and women stood at 1.26 and 0.59 and that of cerebral infarction at 1.87 and 1.10 respectively. The difference in incidence between the sexes was large particularly in the age range of 40-49. The incidence of all types of stroke, cerebral hemorrhage and cerebral infarction increased with age. The incidence of all strokes in Japan during the period 1975-1979 appears to have decreased in comparison with that in 1960-1969, but tended to be still higher than that in Western countries.

The seasonal variation in mortality from cerebrovascular disease

The frequency distribution of deaths from cerebrovascular disease in England and Wales in 1975 by month of occurrence is described. The distribution is compared with that for related diseases, in particular ischaemic heart disease, hypertensive disease, pneumonia and bronchitis. The principal feature in all these diseases is high mortality in winter and spring and low mortality in late summer, but the range of variation is wider for pneumonia and bronchitis. The seasonal distribution of cerebrovascular disease death is similar in both sexes, all ages at death and for deaths at home and deaths in a hospital or institution. For both sexes the proportion of cerebrovascular disease deaths occurring at home increases significantly with age at death. Four hypotheses are examined to explain this characteristic seasonal mortality pattern, which is related inversely to ambient temperature, and similar to the seasonal pattern of the incidence and prevalence of cerebrovascular disease.

Incidence of stroke in Shibata, Japan: 1976-1978

A stroke registry was established in Shibata City, Niigata Prefecture, Japan (population 75,000) in 1976. WHO recommendations for criteria were followed. This paper reports stroke incidence for the initial 3 years of the registry: 1976 through 1978. All living patients were examined clinically by a staff physician. Only patients with a diagnosis of first stroke were included in the study. Sensitivity of the referral system was estimated at 85 + %, comparable to that in American studies. Average annual incidence per 1,000 in resident greater than or equal to 20 years was 2.61 for all strokes (3.42 for males; 1.88 for females), 0.20 for subarachnoid hemorrhage, 0.61 for cerebral hemorrhage, 1.51 for cerebral infarction - rates similar to those reported 10-20 years previously for the United States. The male-female ratio, 2:1, reflected a high rate among males, low among females. Rats among Shibata males were higher than 1972 U.S. rates reported by the Epidemiologic Study Group; rates among Shibata females were lower than corresponding U.S. rates. Incidence of all strokes combined increased with age, the age relationship being strongest for cerebral infarction. No subarachnoid hemorrhage was observed in Shibata residents greater than or equal to 70 years of age.

Sex differences in the incidence of cerebrovascular disease

Incidence rates for cerebrovascular disease reported by community-based and hospital-based studies during the past 15 years are analysed. The range of variation between area is wide, with Japan and Finland experiencing the highest age-adjusted rates. Of 16 studies reporting incidence rates by sex, 15 showed a male excess, and nine of these were significant when the incidence rate was age-adjusted. Overall, the excess is about 30% for both community-bases and hospital-based studies. For cerebral infarction the excess is about 45%. Intracerebral haemorrhage shows little difference between the two sexes and subarachnoid haemorrhage shows a male deficit of about 50%. These findings are self-consistent.

The incidence and economic costs of cancer, motor vehicle injuries, coronary heart disease, and stroke: a comparative analysis

The economic impact of disease and injury has most often been calculated by examining the costs associated with the prevalence of the impairments in the reference year. An alternative accounting approach is to assign all disease costs to the year of incidence, an approach which entails present-valuing to the year of incidence both health care expenditures and lost productivity. The incidence approach is the more appropriate for gauging the economic gains achievable through prevention, immediate rehabilitation, and arresting progression. Incidence-based costs have been estimated for the United States in 1975 for cancer, coronary heart disease, motor vehicle injuries, and stroke. A noteworthy finding is the relative economic importance of motor vehicle injuries, which frequently have been overlooked in the ordering of public health expenditure priorities. After cancer, which generated approximately $23.1 billion in present-valued costs in 1975 (discounted at 6 per cent), motor vehicle injuries and coronary heart disease constitute the next most expensive conditions--having generated estimated annual costs of $14.4 billion and $13.7 billion, respectively. Stroke, at $6.5 billion, follows in economic importance.

Factors related to stroke incidence in Hawaii Japanese men. The Honolulu Heart Study

As part of an ongoing longitudinal study of coronary heart disease and stroke among Japanese men in Hawaii, 8,006 men of Japanese ancestry living on the island of Oahu and aged 45-68 at entry examination have been followed by reexamination and surveillance. One hundred and eleven were found to have evidence of prior stroke at the time of the initial examination. During a six-year follow up period of the remaining 7,895 men, 94 developed definite thromboembolic stroke, 33 definite intracranial hemorrhage, and 6 developed stroke of unknown type. The principal risk factors for thromboembolic stroke were: elevated blood pressure, glucose intolerance, age, and electrocardiography evidence of left ventricular hypertrophy or strain. Attributes associated with increased risk of intracranial hemorrhage were elevated blood pressure, electrocardiographic evidence of left ventricular hypertrophy or strain, and alcohol intake. Serum cholesterol level was negatively associated with risk of intracranial hemorrhage.

A prospective epidemiological survey of cerebrovascular disease in a Swedish community

A prospective epidemiological study of cerebrovascular diseases and transient ischemic attacks (TIA) is presented. During a three-year period the annual incidence of strokes was 2.90 and of TIA 0.45 per thousand population. This difference in incidence and the disparities in age characteristics favour the hypothesis that TIA precedes only a minority of the strokes. The short-term mortality is high among the stroke patients.

Incidence of stroke in Frederiksberg, Denmark

Since 1971, stroke registers in several countries have been cooperating in a study of stroke epidemiology, initiated by WHO. One of the registers covers the population of Frederiksberg, Copenhagen. During the first two years of registration strokes were recorded in 556 Frederiksberg citizens. A certain diagnosis of cerebral hemorrhage--verified by angiography, spinal fluid examination, or autopsy--was made in 10% of the patients; subarachnoid hemorrhage was demonstrated in only 2%; most of the remaining patients probably had cerebral infarction. The overall annual incidence of stroke, when adjusted for age for the Danish population, was 1.9 per 1,000 for males, and 1.6 per 1,000 for females. For every type of stroke, except subarachnoid hemorrhage, the incidence increased markedly with age. The age-specific stroke incidence rates found in the present investigation are much lower than those demonstrated by Aho in a community-based study in Finland. In view of the strict comparability of the two studies, real differences in the risk of stroke may exist between the two communities.

Epidemiology of cerebrovascular disease in Tartu, Estonia, USSR, 1970 through 1973

This study was undertaken to establish the incidence and mortality for various types of cerebrovascular disease in the population of Tartu. All medical records for this population were reviewed for the period 1970 through 1973, and those with a diagnosis of brain infarction, transient ischemic attacks, cerebral hemorrhage or subarachnoid hemorrhage were identified. Only the first stroke was considered when determining incidence. A total of 786 cases were included in the study. Without cases of transient ischemic attacks, the number was 667 (e.g., cases of stroke). Cerebral infarction accounted for 80% of all strokes, cerebral hemorrhage for 13.5% and subarachnoid hemorrhage for 6.5%. The incidence rate for stroke was higher for men than for women and significantly increased in each older age group. The rate for all persons was 184 per 100,000 population per year. The incidence of transient ischemic attacks was 33 per 100,000 population per year. The mortality rate for stroke for this population was 98/100,000 per year. The data on incidence of stroke and its type, its dependence on age and sex, and mortality rate are close to the corresponding data reported from other countries.

Risk factors in stroke: a clinical study in Mexican patients

Mexicans hospitalized between July, 1967, and June, 1968, with clinically diagnosed stroke provided information on risk factors in a population from which little systematically collected information on stroke exists. The patients were beneficiaries of ISSSTE, a government-sponsored health care system. Postmortem examination in 20 patients indicated virtually 100% validity of diagnosis. Cerebral thrombosis, hemorrhage and embolus occurred in a ratio of 6:2:1. There was no sex difference in stroke frequency. Thrombosis and hemorrhage increased with age; embolus occurred more often in younger patients. Thrombosis tended to occur when at repose and in individuals with sedentary occupations; the opposite was found with hemorrhage and embolus. Obesity did not seem to predispose to stroke. Hypertension, heart disease and diabetes mellitus emerged as common antecedent conditions. There was a morning peak in onset of thrombosis and hemorrhage and an afternoon peak for embolus. No relation of onset to holidays or stress was noted. Thrombosis, hemorrhage and embolus all were associated with increased ambient temperature, and with low, slightly decreased and high humidity, respectively. An August-September (end of rainy season) peak in seasonal frequency occurred. The risk factors previously identified as being important mainly in northern populations seemed to be important in this Mexican population as well. Thus, ethnic and cultural variability exerted little effect on stroke frequency.

The epidemiology of stroke in central Harlem

In January, 1971, the Regional Medical Program of New York implemented a comprehensive regional stroke program at Harlem Hospital in cooperation with Columbia University, New York, New York. The program is directed toward prevention, treatment and rehabilitation of stroke patients. During the first year of the program, 395 patients with the diagnosis of acute stroke were admitted. Sixty-seven had not suffered an acute stroke. Of the remaining 328 patients with a verified acute stroke, 52 were classified as hemorrhagic. Only three patients with TIA were seen. One hundred thirteen patients, 40 of whom had suffered hemorrhagic strokes, died while in the hospital. Two hundred thirty-six patients had associated diseases, hypertension being the most common. The median age was 65 for women and 66 for men. Based on the 1970 census, the rate per 100,000 is estimated to be at least 212. Age-specific rates show a higher than expected rate among the younger age groups. Compared with similar studies of white populations, this study indicates the following characteristics of the entity stroke in an urban black community: (1) incidence is high, (2) patients are relatively young, and (3) high incidence of associated disease.

Stroke in Jerusalem district 1960 through 1967: an epidemiological study

An epidemiological study was performed in Jerusalem district on the incidence of new stroke patients during the years 1960 through 1967.

On the assumption that the vast majority of patients with a new cerebrovascular event were either hospitalized in one of the three local hospitals or later referred to the Neurological Outpatient Clinic at the Hadassah University Hospital, a retrospective study was performed in order to obtain a close estimation of the incidence of stroke in the district of Jerusalem. In the period of 1960 through 1967, 1,522 new stroke cases were identified and included in this study. On the basis of the history, clinical picture and auxiliary tests, the patients were divided into three groups: (1) ischemic stroke, (2) stroke due to hemorrhage, and (3) stroke of undetermined type. The criteria for differentiation of cerebral ischemia from hemorrhage were rigid, demanding at least a lumbar puncture, angiography, operation, or autopsy for a diagnosis of either one to be made. These rigid criteria account for the high percentage of undetermined cases. Ischemic stroke was diagnosed in 509 (33%), stroke due to hemorrhage in 181 (12%), and stroke of undetermined type in 832 (55%).

The average annual incidence of stroke in the district of Jerusalem was 90/100,000 population.

The age-specific annual incidence rates showed an almost constant increase for both sexes and the various types of stroke, with increasing age. The age-specific and sexspecific annual incidence rates disclosed a male preponderance for all the age groups above 45 in the "ischemic" and "undetermined" types, and for the total series. This preponderance was marked in the 65 to 74 age group. In the "stroke due to hemorrhage" type there was a slight male preponderance in the 65 to 74 age group and a slight female preponderance in the 75+ age group, the ratio being equal for the total hemorrhagic series. Our findings were compared with those reported in other studies and discussed.