Seasonal variation in strokes incidence and the influence of the meteorological conditions

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.     

Stroke incidence and survival among middle-aged adults: 9-year follow-up of the Atherosclerosis Risk in Communities (ARIC) cohort

BACKGROUND AND PURPOSE: Although stroke mortality rates in the United States are well documented, assessment of incidence rates and case fatality are less well studied. METHODS: A cohort of 15 792 men and women aged 45 to 64 years from a population sample of households in 4 US communities was followed from 1987 to 1995, an average of 7. 2 years. Incident strokes were identified through annual phone contacts and hospital record searching and were then validated. RESULTS: Of the 267 incident definite or probable strokes, 83% (n=221) were categorized as ischemic strokes, 10% (n=27) were intracerebral hemorrhages, and 7% (n=19) were subarachnoid hemorrhages. The age-adjusted incidence rate (per 1000 person-years) of total strokes was highest among black men (4.44), followed by black women (3.10), white men (1.78), and white women (1.24). The black versus white age-adjusted rate ratio (RR) for ischemic stroke was 2.41 (95% CI, 1.85 to 3.15), which was attenuated to 1.38 (95% CI, 1.01 to 1.89) after adjustment for baseline hypertension, diabetes, education level, smoking status, and prevalent coronary heart disease. There was a tendency for the adjusted case fatality rates to be higher among blacks and men, although none of the case fatality comparisons across sex or race was statistically significant. CONCLUSIONS: After accounting for established baseline risk factors, blacks still had a 38% greater risk of incident ischemic stroke compared with whites. Identification of new individual and community-level risk factors accounting for the elevated incidence of stroke requires further investigation and incorporation into intervention planning.     

Migraine history and migraine-induced stroke in the Dijon stroke registry

Two thousand three hundred and eighty-nine patients with first-ever stroke were registered in the population-based Dijon Stroke Registry over an 11-year period. There was a history of migraine in 49 cases (2%), with a majority of women (2.8% versus 1.1% men) with the following distribution: 27 cases among 1,380 large-artery cerebral infarctions (1.9%), 6 cases among 358 small-artery cerebral infarctions (1.6%), 6 cases among 412 cerebral infarctions due to cardiac embolism (1.4%), 7 cases among 191 cerebral hemorrhages (3. 6%) and 3 cases among 47 subarachnoid hemorrhages (6.3%). The male/female ratio was 0.58 for the 49 strokes with a history of migraine versus 1.27 for the 2,340 strokes with no history of migraine. Twelve migraine-induced ischemic strokes occurred with an infarction of the posterior area of the brain in young patients. The annual incidence was 0.80/100,000/year (confidence interval, CI = 0. 37-1.57) with a predominance of women (1.02/100,000/year, CI = 0. 52-1.25; men: 0.57/100,000/year; CI = 0.28-1.04). We conclude that a history of migraine is more frequent in women, in particular in those with hemorrhagic strokes, and that the incidence of migraine-induced stroke in our population-based study is higher in women, although it remains low.     

Widening gap of stroke between east and west. Eight-year trends in occurrence and risk factors in Russia and Sweden

BACKGROUND AND PURPOSE: Stroke is declining in most of the western and northern European countries, whereas no such decline is seen in eastern Europe. The aim of this study was to investigate trends in stroke attack rates and 28-day case fatality and risk factor levels in Novosibirsk, Siberia, and northern Sweden during 1987-1994. METHODS: Within the World Health Organization Multinational Monitoring of Trends and Determinants in Cardiovascular Disease (MONICA) Project, acute stroke events and 28-day case fatality were registered in a standardized way in men and women aged 35 to 69 years. Cardiovascular risk factors were monitored in randomly selected men and women in the group aged 35 to 64 years in 1985-1986 and 1994-1995. RESULTS: Stroke attack rates increased significantly from 430 per 100 000 to 660 (P=0.005) in men in Novosibirsk and from 298 to 500 (P=0.02) in women. In northern Sweden, stroke attack rates varied between 244 and 303 per 100 000 in men and from 117 to 157 in women, with a small increasing trend in women (P=0.03). The mortality rates were 5 times higher in Novosibirsk, and the case fatality was significantly lower in northern Sweden (P=0.0001). The risk factor surveys showed significantly higher blood pressure, overweight, and more smoking men in Novosibirsk, while northern Sweden had higher cholesterol levels and more smoking women. Most risk factors showed stable or improving patterns over time. CONCLUSIONS: Large differences in both attack rates and case fatality account for the large and widening gap in stroke mortality between Russia and Sweden. A higher prevalence of hypertension in Russia may explain much of the differences in stroke occurrence. In Russia, a marked increase in attack rates has occurred despite stable or improving patterns of conventional cardiovascular risk factors.     

Secular trends in stroke incidence and mortality. The Framingham Study.

BACKGROUND: The reduction in US stroke mortality has been attributed to declining stroke incidence. However, evidence is accumulating of a trend in declining stroke severity. METHODS: We examined secular trends in stroke incidence, prevalence, and fatality in Framingham Study subjects aged 55-64 years in three successive decades beginning in 1953, 1963, and 1973. RESULTS: No significant decline in overall stroke and transient ischemic attack incidence or prevalence occurred. In women, but not men, incidence of completed ischemic stroke declined significantly. Stroke severity, however, decreased significantly over time. Stroke with severe neurological deficit decreased in later decades, with a fall in rates of severe stroke cases in which patients were unconscious on admission to the hospital. There was no substantial change in the case mix of infarcts and hemorrhages and no decline in hemorrhage to account for the decline in severity. The proportion of isolated transient ischemic attacks increased significantly over the 30 years studied, yielding an apparent and significant decline in case-fatality rates in men only. CONCLUSIONS: Secular trends in stroke incidence and fatality did not follow a clear or definite pattern of decline. While a significant decline in stroke severity occurred over three decades, incidence of infarction fell only in women. The decline in total case fatality rates occurred only in men and resulted largely from an increased incidence of isolated transient ischemic attacks. The severity of completed stroke was significantly lower in the later decades under study.     

Stroke Risk Due to Smoking Characterized by Sex Differences in Japan: The Jichi Medical School Cohort Study

ObjectivesSmoking is a risk factor for stroke. The relationship between smoking and the risk of different subtypes of stroke has not been fully elucidated. We investigated the relationship between smoking and the incidence of stroke in the Japanese population.Materials and methodsThis prospective, population-based cohort study included 11,324 participants (4447 men; 6877 women) from 12 districts in Japan, between April 1992 and July 1995. Participants were stratified according to smoking status (non-smoker [never smoked]/ex-smoker/current smoker). Male current smokers were further stratified according to the number of cigarettes smoked per day (1–14, 15–29, or ≥ 30). The non-smoking group was used as a reference. Cox proportional hazards analysis was used to determine the risk of stroke due to smoking.ResultsFour hundred and seventeen new stroke events (212 men; 205 women) were recorded during a mean follow-up of 10.7 years, including 95 intracerebral hemorrhages (48 men; 47 women), 267 cerebral infarctions (152 men; 115 women), and 54 subarachnoid hemorrhages (12 men; 42 women). In multivariable analysis, the hazard ratios (95% confidence intervals) for male current smokers (≥ 30 cigarettes/day) were 1.89 (1.08–3.31) and 3.41 (1.22–9.57) for all strokes and intracerebral hemorrhages, respectively; those for female current smokers were 2.78 (1.62–4.74), 3.14 (1.51–6.54), and 4.03 (1.64–9.93) for all strokes, cerebral infarctions, and subarachnoid hemorrhages, respectively.ConclusionsSmoking ≥ 30 cigarettes/day is a risk factor for stroke, especially intracerebral hemorrhage in men. Furthermore, smoking increases the risk of cerebral infarction and subarachnoid hemorrhage in women.     

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

BACKGROUND AND PURPOSE: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.     

Stroke in China (Sino-MONICA-Beijing study) 1984-1986.

We present here the results of the Sino-MONICA-Beijing stroke study based on 700,000 Beijing residents in 1984-1986. To compare incidence rates for stroke with other communities and countries, we adopted the criteria of the WHO Collaborative Study of 17 centers which used the same definition and methodology as was used in this study. Over the 3-year period of the study, 2,593 stroke events were registered in the 25- to 74-year age-group. The incidence rate for all strokes was 189.5/100,000 and the incidence rate for first strokes was 133.6/100,000. Men had a significantly higher incidence rate than women (all strokes 219.7/100,000 for male vs. 160.5/100,000 for female, OR = 1.32, 99% limits 1.19-1.46; first strokes 151.6/100,000 for male vs. 116.4/100,000 for female, OR = 1.25, 99% limits 1.11-1.42). In comparison with other studies, age-adjusted incidence rate of stroke in Beijing was higher than in other countries, especially for hemorrhagic stroke. The proportion of hemorrhagic stroke related to other types of stroke was also higher in Beijing. Further analysis of the cases confirmed by computerized tomography also supported this finding. Unlike the incidence rates, the 4-week case fatality rate for women, 39.5%, was higher than for men, 32.8%. This finding was confirmed by a multiple logistic analysis controlling for age (p less than 0.001) and for previous stroke (p less than 0.001). The adjusted sex difference is also significant (OR = 1.37, p less than 0.001). In addition, results showed that men had a higher hospitalization rate than women. More women than men were treated at home, possibly indicating better medical care for men.     

Poststroke depression and emotional incontinence: correlation with lesion location

OBJECTIVE: To correlate the location of stroke with poststroke depression (PSD) and emotional incontinence (PSEI). METHODS: The authors prospectively studied 148 patients (94 men and 54 women, mean age 62 years) with single, unilateral stroke (126 infarcts and 22 hemorrhages) at 2 to 4 months poststroke with regard to the presence of PSD (using Diagnostic and Statistical Manual of Mental Disorders IV criteria and Beck Depression Inventory) and PSEI. The lesion location was analyzed by CT or MRI. RESULTS: Twenty-seven patients (18%) had PSD and 50 (34%) had PSEI. The presence of PSD and PSEI was not related to the nature, laterality, or size of the lesion. The frequency of PSEI, but not of PSD, was higher in women than in men and in ischemic rather than hemorrhagic stroke (p < 0. 05). Although both PSD and PSEI were related to motor dysfunction and location (anterior versus posterior cortex) of the lesion, location was a stronger determinant for PSD (p < 0.05). The prevalence of PSD/PSEI in each location was 75%/100% in frontal lobe of anterior cerebral artery territory, 50%/0 in temporal lobe, 30%/40% in frontal-middle cerebral artery territory, 13%/0 in occipital lobe, 19%/45% in lenticulocapsular area, 11%/16% in thalamus, 16%/53% in pontine base, 36%/55% in medulla, and 0/22% in cerebellum. Parietal and dorsal pontine lesions were not associated with PSD or PSEI. PSEI was more closely associated with lenticulocapsular strokes than was PSD (p < 0.01). CONCLUSION: Development of PSD and PSEI is strongly influenced by lesion location, probably associated with the chemical neuroanatomy related to the frontal/temporal lobe-basal ganglia-ventral brainstem circuitry. Although the lesion distribution is similar, PSEI is more closely related to lenticulocapsular strokes than is PSD.     

Cerebrovascular disease in Saudi Arabia

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

Estimates of stroke incidence and case fatality in Zabrze, 2005-2006

Background and purposeEpidemiological rates for stroke obtained in the United States and Western Europe indicate a decrease in incidence and case fatality. Data published for Poland, as for other Central-Eastern European countries, reported unfavourable results, but this was based on data from the 1990s. The authors evaluated current stroke rates in a population study of the southern Poland city of Zabrze.Material and methodsA retrospective registry of all stroke cases treated in Zabrze, southern Poland, in 2005–2006, was established, based on data from the National Health Fund. Cases were identified by verifying patient files. Epidemiological rates were calculated and standardized to the European population in both groups: all stroke patients, including recurrent (all strokes, AS), and patients with first-ever stroke (FES) in their history.ResultsWe registered 731 strokes, including 572 FES cases (78.3%) and 159 recurrent strokes (21.7%). There were 385 strokes in men (52.7%), and 346 in women (47.2%); 88.6% were ischaemic strokes (IS), and 11.4% were intracerebral haemorrhages (ICH). The standardized incidence rate for AS patients was 167/100 000 (211 for men, 130 for women), and in the FES group 131/100 000 (161 for men, 104 for women). Twenty-eight day case fatality for the AS group was 18.3% (15.4% for IS, 41% for ICH), and 16.6% for FES (13.4% for IS, 40.9% for ICH).ConclusionsIncidence rates in this southern Poland city are comparable to those reported previously for Poland. Early case fatality decreased, compared to previous data, probably as a result of improved management of acute stroke and hospitalizing all stroke patients.     

Mechanisms of acute cerebral infarctions in patients with middle cerebral artery stenosis: a diffusion-weighted imaging and microemboli monitoring study

Although most therapeutic efforts and experimental stroke models focus on the concept of complete occlusion of the middle cerebral artery as a result of embolism from the carotid artery or cardiac chamber, relatively little is known about the stroke mechanism of intrinsic middle cerebral artery stenosis. Differences in stroke pathophysiology may require different strategies for prevention and treatment. We prospectively studied 30 consecutive acute ischemic stroke patients with middle cerebral artery stenosis detected by transcranial Doppler and magnetic resonance angiography. Patients underwent microembolic signal monitoring by transcranial Doppler and diffusion-weighted magnetic resonance imaging. Characteristics of acute infarct on diffusion-weighted magnetic resonance imaging were categorized according to the number (single or multiple infarcts) and the pattern of cerebral infarcts (cortical, border zone, or perforating artery territory infarcts). The data of microembolic signals and diffusion-weighted magnetic resonance imaging were assessed blindly and independently by separate observers. Diffusion-weighted magnetic resonance imaging showed that 15 patients (50%) had single acute cerebral infarcts and 15 patients had multiple acute cerebral infarcts. Among patients with multiple acute infarcts, unilateral, deep, chainlike border zone infarcts were the most common pattern (11 patients, 73%), and for single infarcts, penetrating artery infarcts were the most common (10 patients, 67%). Microembolic signals were detected in 10 patients (33%). The median number of microembolic signals per 30 minutes was 15 (range, 3-102). Microembolic signals were found in 9 patients with multiple infarcts and in 1 patient with a single infarct (p = 0.002, chi(2)). The number of microembolic signals predicted the number of acute infarcts on diffusion-weighted magnetic resonance imaging (linear regression, adjusted R(2) =0.475, p < 0.001). Common stroke mechanisms in patients with middle cerebral artery stenosis are the occlusion of a single penetrating artery to produce a small subcortical lacuna-like infarct and an artery-to-artery embolism with impaired clearance of emboli that produces multiple small cerebral infarcts, especially along the border zone region.     

The Saudi Stroke Data Bank Analysis of the first 1000 cases

OBJECTIVES: To determine the types of stroke, their risk factors and their most likely causes in Saudi patients. METHODS: Data on stroke cases admitted to 2 major hospitals in Saudi Arabia since 1982 were collected retrospectively up to 1991 then prospectively since then. By January 1995, the number of cases with first-ever-stroke stored in our Saudi Stroke Data Bank reached 1280. This article describes the findings in the first 1000 Saudi patients investigated by brain computed tomography. RESULTS: Males (68%) outnumbered females. There was no significant difference between the retrospective cases and the prospective ones in relation to the types of stroke or the risk factors. Ischemic strokes accounted for 76% of the cases and one third of them were lacunar infarcts. Most of the hemorrhagic strokes were intracerebral hemorrhages (ICHs) and only 2% of all strokes were subarachnoid hemorrhages (SAHs). Hypertension (52%), diabetes mellitus (41%) and cardiac disorders were common risk factors. The commonest causes of cerebral infarcts were atherosclerosis 36%, hypertensive and/or diabetic arteriolopathy 24% and cardiac embolisms 19%. Hypertensive arteriolopathy accounted for two-thirds of the cerebral hemorrhages. Strokes related to small artery disease, i.e. lacunar infarcts and ICHs accounted for 47% of the cases. CONCLUSION: The overall distribution of stroke types in Saudis is not very different from that reported in western studies, except for the low frequency of SAH. However, the important role of small artery disease in stroke pathogenesis and the high number of diabetic patients are quite distinctive.     

A multinational comparison of subarachnoid hemorrhage epidemiology in the WHO MONICA stroke study

BACKGROUND AND PURPOSE: By official, mostly unvalidated statistics, mortality from subarachnoid hemorrhage (SAH) show large variations between countries. Using uniform criteria for case ascertainment and diagnosis, a multinational comparison of attack rates and case fatality rates of SAH has been performed within the framework of the WHO MONICA Project. METHODS: In 25- to 64-year-old men and women, a total of 3368 SAH events were recorded during 35.9 million person-years of observation in 11 populations in Europe and China. Strict MONICA criteria were used for case ascertainment and diagnosis of stroke subtype. Case fatality was based on follow-up at 28 days after onset. RESULTS: Age-adjusted average annual SAH attack rates varied 10-fold among the 11 populations studied, from 2.0 (95% CI 1.6 to 2.4) per 100 000 population per year in China-Beijing to 22.5 (95% CI 20.9 to 24.1) per 100 000 population per year in Finland. No consistent pattern was observed in the sex ratio of attack rates in the different populations. The overall 28-day case fatality rate was 42%, with 2-fold differences in age-adjusted rates between populations but little difference between men and women. Case fatality rates were consistently higher in Eastern than in Western Europe. CONCLUSIONS: Using a uniform methodology, the WHO MONICA Project has shown very large variations in attack rates of SAH across 11 populations in Europe and China. The generally accepted view that women have a higher risk of SAH than men does not apply to all populations. Marked differences in outcome of SAH add to the wide gap in the burden of stroke between East and West Europe.     

Intracerebral hemorrhage survival: French register data

Cerebral hemorrhages are subject to a heavy short- and long-term case fatality. A study of prognostic factors and of relative survival based on the data of a population registry is of great value to study patients having a hematoma of all ages, irrespective of the method of care. We have listed 183 patients having a cerebral hemorrhage between 1 January 1985 and 31 December 1996 and living in the city of Dijon, France. Eighteen clinical and CT-scanning variables have been studied. We have found four predictive factors of death at one month from cerebral hemorrhages. These are, in decreasing order: the existence of consciousness disorders at the initial clinical examination (OR = 5.80, p < 0.0001); an intraventricular hemorrhage (OR = 5.60, p < 0.0001); a hematoma volume over 11 cubic centimeters (OR = 3.53, p = 0.027); lastly, in male patients an age over 70 years (OR = 4.90, p = 0.039). With regard to long-term survival, the existence of consciousness disorders remains the principal predictive factor of case fatality in both crude and relative survival (OR = 5.52, p < 0.0001, in crude survival versus OR = 22.2 in relative survival, p < 0.0001), followed by age over 70 years (OR = 3.71, p < 0.0001 in crude survival and OR = 2.41 in relative survival, p = 0.086). The existence of consciousness disorders at the initial examination following a cerebral hemorrhage would seem to be the principal worst prognostic factor of short- and long-term survival and of relative survival, age and sex having less importance. Moreover, intraventricular hemorrhage and hematoma volume are short-term, pejorative factors. These data, based on a population-based registry, are an important consideration in the acute management of hemorrhagic therapy, and for the design of further therapeutic trials on this severe pathology.     

Stroke attack rates and case fatality in the Krakow Stroke Registry

BACKGROUND AND PURPOSE: Previous epidemiological studies of stroke in Poland completed more than 10 years ago reported moderate incidence rates but very high case fatality rates due to stroke. We used the data of the Krakow Stroke Registry to calculate the attack rates as well as short- and long-term case fatality rates from stroke in hospitalized inhabitants of Krakow, Poland. MATERIAL AND METHODS: We prospectively recorded all cases of stroke (defined according to the ICD-10) in adult permanent residents of Krakow, who were admitted to hospitals in that city. The registration took one year (between 1 July 1999 and 30 June 2000). The vital status of participants was established on days 30, 90 and 180 and at one year after their stroke. RESULTS: 1096 strokes occurred in a population of 589,820. Attack rate standardized for the European population was 180.0 per 100,000 (218.3 in men and 151.9 in women). Ischaemic stroke was diagnosed in 532 (48.6%), stroke not specified as haemorrhagic or ischaemic in 406 subjects (37.0%), intracerebral haemorrhage in 86 (7.8%), and subarachnoid haemorrhage in 72 (6.6%). The 30-day, 90-day, 180-day and one-year case fatality rates for all strokes were 17.8%, 28.1%, 30.8% and 39.7%, respectively. Case fatality rates for ischaemic stroke were 9.8%, 19.0%, 21.6% and 31.2%, respectively and for intracerebral haemorrhage 44.2%, 55.8%, 55.8% and 60.5%, respectively. CONCLUSIONS: The attack rates of stroke in urban areas of Poland are similar to the average European rates. Short- and long-term case fatality rates are much lower than previously reported.     

Decreased severity of brain infarct can in part explain the decreasing case fatality rate of stroke

BACKGROUND AND PURPOSE: Case fatality rates for stroke has declined in most Western industrialized countries during recent decades. One possible explanation for this is a decrease in the severity of stroke symptoms. We therefore sought evidence for a change in stroke severity and its relationship with case fatality rates. METHODS: We compared the severity of symptoms among first-ever stroke patients in 2 population-based prospective stroke registers maintained during 1972 to 1973 and 1989 to 1991 in Finland. Patients who were evaluated by study assistants or the investigator during the first week after the onset of symptoms were included in the study, and their severity of symptoms was assessed with the use of comparable scales modified from the Scandinavian Stroke Scale. RESULTS: A total of 244 and 594 patients were registered, and a portion of them (155 [63.5%] and 360 [60.6%]) were included in the analyses in the registers for Espoo-Kauniainen from 1972 to 1973 and for 4 separate districts in Finland from 1989 to 1991, respectively. The death rates during the first week among those who were not included did not differ between the registers. The severity of symptoms decreased significantly between the registers in both patients with brain infarct or intracerebral hemorrhage but not in those with subarachnoid hemorrhage. The severity of symptoms was an independent factor of case fatality at 1 month. CONCLUSIONS: The severity of symptoms of brain infarcts has decreased and can in part explain the decreased case fatality rate of stroke in Finland. However, the change in patients with intracerebral hemorrhage may be overestimated due to undiagnosed intracerebral hemorrhages in the first register resulting from the lack of brain CT.     

Annual incidence of first silent stroke in the United States: a preliminary estimate

BACKGROUND: Recent estimates of stroke incidence in the US range from 760,000 to 780,000 annually, however these estimates do not reflect the incidence of silent infarcts and hemorrhages. Since population-based studies indicate the prevalence of silent stroke is substantially higher than that of symptomatic stroke, estimates of stroke incidence based solely on symptomatic events may substantially underestimate the annual stroke burden. METHODS: The prevalence of silent infarcts for different age strata were abstracted from two US population-based MRI studies, the Atherosclerosis Risk in Communities Study and the Cardiovascular Health Study. Similarly, first silent cerebral hemorrhage incidence rates were derived from population-based MRI prevalence observations in the Austrian Stroke Prevention Study. Prevalence observations in these studies and death rates from the US Census were inputted to calculate age-specific first silent MRI infarct and hemorrhage incidence. Age- specific incidence rates were projected onto 1998 US population age cohorts to calculate the annual burden of first silent MRI ischemic stroke and first silent MRI cerebral hemorrhage. RESULTS: Estimated age-specific annual incidence rates (per 100,000) of persons experiencing first silent MRI infarct ranged from 1,600 in the age 30-39 stratum to 16,400 at ages 75-79. Estimated incidence rates of first silent MRI cerebral hemorrhage ranged from 180 in the ages 30-39 to 6,900 at age >85. Overall, the projected annual incidence in 1998 of US individuals experiencing first silent MRI infarct was 9,040,000, and first silent MRI hemorrhage 1,940,000. CONCLUSIONS: In 1998, more than 11 million persons experienced stroke in the US, in whom approximately 770,000 were symptomatic and 11 million were first-ever silent MRI infarcts or hemorrhages. These findings demonstrate the incidence of stroke is substantially higher than suggested by estimates based solely on clinically manifest events.     

Is there any circadian variation consequence on acute case fatality of stroke? Takashima Stroke Registry,Japan (1990–2003)

Turin TC, Kita Y, Rumana N, Nakamura Y, Takashima N, Ichikawa M, Sugihara H, Morita Y, Hirose K, Okayama A, Miura K, Ueshima H. Is there any circadian variation consequence on acute case fatality of stroke? Takashima Stroke Registry, Japan (1990–2003).
Acta Neurol Scand: 2012: 125: 206–212.
© 2011 John Wiley & Sons A/S. Background – Circadian periodicity in the onset of stroke has been reported. However, it is unclear whether this variation affects the acute stroke case fatality. Time of the day variation in stroke case fatality was examined using population‐based stroke registration data. Methods – Stroke event data were acquired from the Takashima Stroke Registry, which covers a stable population of ≈55,000 in Takashima County in central Japan. During the period of 1990–2003, there were 1080 (549 men and 531 women) cases with classifiable stroke onset time. Stroke incidence was categorized as occurring at night (midnight‐6 a.m.), morning (6 a.m.‐noon), afternoon (noon‐6 p.m.), and evening (6 p.m.‐midnight). The 28‐day case fatality rates and 95% confidence intervals (95% CI) were calculated by gender, age, and stroke subtype across the time blocks. After adjusting for gender, age at onset, and stroke severity at onset, the hazard ratios for fatal strokes in evening, night, and morning were calculated, with afternoon serving as the reference. Results – For all strokes, the 28‐day case fatality rate was 23.3% (95% CI:19.4–27.6) for morning onset, 16.9% (95% CI:13.1–21.6) for afternoon onset, 18.3% (95% CI:13.6–24.1) for evening onset, and 21.0% (95% CI:15.0–28.5) for the night onset stroke. The case fatality for strokes during the morning was higher than the case fatality for strokes during afternoon. This fatality risk excess for morning strokes persisted even after adjusting for age, gender, and stroke severity on onset in multivariate analysis. Conclusion – In the examination of circadian variation of stroke case fatality, 28‐day case fatality rate tended to be higher for the morning strokes.