Stroke incidence and risk factors for stroke in Copenhagen, Denmark

Stroke incidence in Copenhagen, Denmark was recorded in a random population sample of 19,327 persons invited for two health examinations with 5 years' interval from 1976 to 1983. Stroke incidence increased exponentially with age. After adjustment to the age and sex distribution of the Danish population in 1980, the estimated incidence of first stroke was 1.41/1000 women and 2.48/1000 men; the total incidence was 1.94/1000 population. Risk factor analysis was based on the initial examination of 13,088 persons greater than 35 years old without previous stroke who responded to the first invitation, in whom 295 first strokes were subsequently observed. We used the regression model of Cox. However, our use of this model differs from the somewhat automatic procedures normally used to develop prognostic models. Evaluation of the causative effect of a particular risk factor requires that the direction of mutual influences between the factor in question and other risk factors is established/postulated. Among the 16 potential risk factors for stroke we examined, significant effects were found for age, sex, household income, smoking habits, systolic blood pressure, diabetes, plasma cholesterol concentration, ischemic heart disease, and atrial fibrillation. No significant effect could be demonstrated for a positive family history of stroke, years of school education, marital status, alcohol consumption, daily use of tranquilizers, body mass index, or postmenopausal hormone treatment.     

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.     

Trends in medical care of hospitalized stroke patients between 1980 and 1990: The minnesota stroke survey.

Recent decades have seen several advances in medical care for acute stroke patients, but there has been little systematic documentation of these changes. This study examined changes in technology use and medical therapies for hospitalized acute stroke during the 1980s. For 1980, 1985, and 1990, we obtained discharge diagnosis lists from Minneapolis-St Paul metropolitan hospitals, identified hospitalizations for acute stroke of patients aged 30 to 74 years, and selected a 50% random sample. Trained nurses abstracted the medical records. Strokes were classified as hemorrhagic or ischemic based on discharge diagnosis code (using the International Classification of Diseases, 9th Revision) and findings from computed tomography (CT) or magnetic resonance imaging (MRI). Strokes classified as ischemic totaled 459 in 1980, 549 in 1985, and 657 in 1990. There were approximately 100 hemorrhagic stroke patients in each survey year. Throughout the 1980s, there was a trend toward both greater and earlier use of CT and MRI to diagnose stroke. By 1990, only 3% of patients did not receive CT or MRI during the acute hospital stay, and the percentage of patients scanned on the first day of hospitalization almost doubled from 43% in 1980 to 76% in 1990 (P=.0001). For ischemic stroke patients, the use of carotid ultrasound doubled from 24% to 48% between 1985 and 1990 (P<.0005), and the probability of identifying a possibly embolic source increased from 27% in 1980 to 40% in 1990 (P<.0005). The use of anticoagulants to treat ischemic stroke decreased from 1985 to 1990 (heparin, 53% to 47%, P=.030; coumadin, 37% to 31%, P=.032), whereas the use of aspirin increased by over 50% (from 27% to 41%, P<.0005). Finally, the mean length of stay was halved from 20 days in 1980 to 10 days in 1990 (P=.0001). This study documented several significant time trends in acute stroke care. Whether these trends account for some of the improvement in stroke survival during the 1980s is uncertain.     

Association between FSP,CVHI, inflammatory cytokines and the incidence of primary stroke

This case-control study was designed to establish a new risk-prediction model for primary stroke using Framingham stroke profile (FSP), cerebral vascular hemodynamic indexes (CVHI) and plasma inflammatory cytokines including hs-CRP, IL-6, TNF-α and Lp-PLA2. A total of 101 primary stroke patients admitted to Dongguan Houjie Hospital between August 2014 and June 2015 were assigned into the case group, and 156 age- and gender-matched healthy subjects from the Houjie Community were allocated into the control group. The prognostic values of FSP, CVHI and inflammatory cytokines including high sensitive C-reactive protein (hs-CRP), interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α) and lipoprotein-associated phospholipase A2 (Lp-PLA2) were assessed by multivariate logistic regression analysis. Seven risk-prediction models (FSP, CVHI, inflammatory cytokine, FSP + CVHI, FSP + inflammatory cytokine, CVHI + inflammatory cytokine, CVHI + FSP + inflammatory cytokine) were successfully established and the prognostic values were statistically compared by ROC curve and Z test. For FSP, the stroke risk was significantly elevated by 2.85 times when the FSP score was increased by 1 level (P = 0.043), increased by 3.25 times for CVHI (P = 0.036), 6.53 times for IL-6 (P = 0.003), and 7.75 times for Lp-PLA2 (P = 0.000). The sensitivity of FSP + CVHI + inflammatory cytokine and CVHI + inflammatory cytokine models was higher than 90%. For model specificity, the specificity of FSP + CVHI + inflammatory cytokine model alone exceeded 90%. FSP, CVHI, IL-6 and Lp-PLA2 are independent risk factors of stroke. Integrating IL-6 and Lp-PLA2 into the models can significantly enhance the risk prediction accuracy of primary stroke. Combined application of FSP + CVHI + inflammatory cytokine is of potential for risk prediction of primary stroke.     

Relationship between longitudinal changes in blood pressure and stroke incidence

The relationship of changes in blood pressure with time to stroke incidence was examined on members of the Adult Health Study sample who have participated in biennial clinical examinations at the Radiation Effects Research Foundation since their inception in 1958. The regression coefficient of blood pressure regressed on time (the increase in blood pressure per cycle) was used as an index of the change in blood pressure with time. Cox's regression analysis, a technique which is suitable for follow-up studies was used. The data suggest that a single blood pressure measurement is not sufficient for predicting risk; the accumulated value or average over a period of time should be considered for this purpose. In addition to the actual blood pressure, the increase in blood pressure with time is a risk factor, particularly for cerebral hemorrhage. Cerebral hemorrhage was more strongly related to diastolic than to systolic blood pressure, while cerebral infarction appeared to be more strongly related to systolic than to diastolic blood pressure.     

Epidemiologic studies of coronary heart disease and stroke in Japanese men living in Japan, Hawaii and California: incidence of stroke in Japan and Hawaii

As part of the Ni-Hon-San Study, stroke incidence was compared in the Japan and Hawaii cohorts. Stroke cases were classified in two types, intracranial hemorrhage (ICH) and thrombo-embolic stroke (T-E). For each type the incidence in Japan was about three times as great as in Hawaii. The ratio ICH/T-E was 1/2.2 and 1/1.6 in Japan and Hawaii, respectively. Blood pressure was the most important risk factor, followed by age for total stroke in both Japan and Hawaii. Proteinuria was also a risk factor in Hawaii. Conversely, an index of animal food intake was inversely related to total stroke, significantly in Hawaii, and at a suggestive level for total and hemorrhagic stroke in Japan. Since the levels of blood pressure do not differ between Japan and Hawaii, one possible explanation for the large difference in stroke incidence between the two cohorts may be the fact that animal protein and saturated fat intake, which is inversely associated with stroke incidence, is much greater in Hawaii than in Japan. This explanation would support epidemiologic and experimental studies in Japan which suggest that dietary animal protein and fat exert an inhibitory effect on the incidence of stroke.     

Increased stroke incidence in Lund-Orup, Sweden, between 1983 to 1985 and 1993 to 1995

BACKGROUND AND PURPOSE: Some studies suggest that the incidence of stroke may continue to change. We examined recent temporal trends in a defined geographical area of southern Sweden. METHODS: Medical records at the University Hospital of Lund (hospital district population 224 126 in 1993) were retrospectively screened for possible first-ever strokes during 1993 to 1995. Included patients were classified into pathological subtypes (cerebral infarction, intracerebral hemorrhage, subarachnoid hemorrhage, and undetermined pathological type) and according to the Oxfordshire Community Stroke Project (OCSP) classification system. Stroke patients from a previous study from 1983 to 1985 in the same area were reevaluated with the same criteria. Epidemiological data for the 2 time periods were compared. RESULTS: There were 998 patients with first-ever stroke in 1983 to 1985 and 1318 in 1993 to 1995. The total incidence rate per 100 000 person-years (age-adjusted to the European population) increased from 134 (95% confidence limits [CL] 126 to 143) to 158 (95% CL 149 to 168). The incidence rate for patients <75 years of age increased from 94 (95% CL 85 to 103) in 1983 to 1985 to 117 (95% CL 108 to 127) in 1993 to 1995, whereas the incidence rate for patients >/=75 years was stable. The age-adjusted incidence rates for the OCSP subtypes lacunar and posterior circulation syndromes increased significantly, by 30% and 55%, respectively. CONCLUSIONS: A marked increase in the incidence of first-ever stroke was observed, surprisingly mainly confined to people <75 years of age. The underlying causes of this increase must be explored in future studies.     

Trends in long-stay hospitalization in Denmark: a descriptive register study, 1972-1987

By means of 4 cross-sections at 5-year intervals from 1972 to 1987, information on long-stay inpatients and daypatients was extracted from the computerized, cumulative psychiatric case register in Denmark. Long-stay refers to continuous hospitalization of more than 1 year. The prevalence of long-stay patients declined from 101 per 100,000 general population in 1972 to 38 per 100 000 in 1987. As the prevalence of all diagnoses declined, regardless of age and sex, it is suggested that the major cause of the observed trends is altered political and administrative strategies, influenced by and influencing altered capabilities and methods of treatment. The trends are described in detail and their implications discussed.     

高血压病患者血压各参数与其并发脑卒中的关系

目的探讨高血压病患者血压各参数与其发生脑卒中的关系。方法回顾性分析798例高血压病患者。年龄45．65岁,其中单纯高血压病患者400例,高血压并发脑卒中者398例,分析两组患者的血压各参数关系,探讨收缩压、舒张压、平均血压、脉压与高血压并发脑卒中的相关性。结果收缩压、平均血压、脉压：脑卒中组与单纯高血压组比较有显著性差异（P〈0．05,P〈0．01）;舒张压：脑卒中组与单纯高血压组比较无显著性差异（P〉0．05）。结论中老年高血压病患者,收缩压、平均血压、脉压与脑卒中的发生有显著相关性,舒张压与脑卒中的发生无显著相关性。     

SEPIVAC: a community-based study of stroke incidence in Umbria, Italy.

The SEPIVAC study is a community-based epidemiological survey of incidence and outcome of acute cerebrovascular disease in the Sixth Local Health Unit, Umbria, Italy (population 49,218). The study was carried out from 1 September 1986 to 31 August 1989. There were 375 patients who were registered with a first ever stroke, with a crude rate of 2.54 (95% confidence limits 2.29-2.81) per 1000 per year; the rate adjusted to the European population is 1.55 (CL 1.36-1.77). The age adjusted relative risk for males is 1.35 (CL 1.10-1.66). Up to 15% of the patients were not admitted to hospital during the acute phase of their disease. At least 286 (76.3%, CL 72-80.6) of the cases were due to cerebral ischaemia; in 56 of these (19.6%, CL 15-24.2) a clinical diagnosis of lacunar ischaemia was made. The 30 day case fatality rate was 20.3% (CL 16.2-24.3); between one and six months 7.5% (CL 5-10.6) of patients died.     

Trends in the incidence, severity, and short-term outcome of stroke in perth, Western Australia.

BACKGROUND AND PURPOSE: This report describes trends in the key indices of cerebrovascular disease over 6 years from the end of the 1980s in a geographically defined segment of the city of Perth, Western Australia. METHODS: Identical methods were used to find and assess all cases of suspected stroke in a population of approximately 134 000 residents in a triangular area of the northern suburbs of Perth. Case fatality was measured as vital status at 28 days after the onset of symptoms. Data for first-ever strokes and for all strokes for equivalent periods of 12 months in 1989-1990 and 1995-1996 were compared by age-standardized rates and proportions and Poisson regression. RESULTS: There were 355 strokes in 328 patients and 251 first-ever strokes (71%) for 1989-1990 and 290 events in 281 patients and 213 first-ever strokes (73%) for 1995-1996. In Poisson models including age and period, overall trends in the incidence of both first-ever strokes (rate ratio=0.75; 95% confidence limits, 0.63, 0.90) and all strokes (rate ratio=0.73; 95% confidence limits, 0.62, 0.85) were obviously significant, but only the changes in men were independently significant. Case fatality did not change, and the balance between hemorrhagic and occlusive strokes in 1995-1996 was almost indistinguishable from that observed in 1989-1990. CONCLUSIONS: Our results, which are the only longitudinal population-based data available for Australia for key indices of stroke, suggest that it is a change in the frequency of stroke, rather than its outcome, that is chiefly responsible nationally for the fall in mortality from cerebrovascular disease.     

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.     

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.     

Evidence for age-dependent education-related differences in men and women with first-ever stroke. Results from a community-based incidence study in northern Sweden

Several studies have shown a relationship between low socioeconomic status, age and stroke mortality. However, there is lack of similar studies in relation to stroke incidence. All cases of first-ever stroke occurring in a population aged 35-85 years from the city of Ume? were collected from hospital-based registers during a 2-year study period (2000-2002), from death certificates and also from nursing homes during a 6-month period. The WHO definition of stroke was used. Register data served to analyze educational level. A total of 457 first-ever strokes (244 women and 213 men) were registered, corresponding to an overall annual incidence rate of first-ever stroke of 413.4 per 100,000. The incidence of first-ever stroke was significantly higher among low-educated compared to high-educated men and women. The highest stroke incidence was found among low-educated women aged 75-85 years. The educational-related differences in stroke incidence persisted in the oldest age group (75-85 years), also after controlling for sex and age. This is one of the first studies that analyzes first-ever stroke incidence also among elderly men and women (75-85 years) in relation to socioeconomic status. More community-based studies are needed in order to confirm the results.     

Comparison of risk factors for stroke incidence and stroke mortality in 20 years of follow-up in men and women in the Renfrew/Paisley Study in Scotland

BACKGROUND AND PURPOSE: The aim of this study was to relate risk factors in middle-aged men and women to stroke incidence (defined by having a hospital discharge with a main diagnosis of stroke) and compare this with the associations between risk factors and stroke mortality. METHODS: In the early to mid-1970s, when they were 45 to 64 years of age, 7052 men and 8354 women from the Renfrew/Paisley prospective cohort study in Scotland were screened. Risk factors measured included blood pressure, blood cholesterol and glucose, respiratory function, cardiothoracic ratio, smoking habit, height, body mass index, preexisting coronary heart disease, and diabetes. These were related to stroke incidence over 20 years of follow-up. RESULTS: Diastolic and systolic blood pressure, smoking, cardiothoracic ratio, preexisting coronary heart disease, and diabetes were positively related to stroke incidence for men and women, whereas adjusted FEV(1) (forced expiratory volume in 1 second) and height were negatively related. Cholesterol was not related to stroke. Glucose for nondiabetic subjects had a U-shaped relationship with stroke. Body mass index was not clearly related to stroke, although participants with the highest body mass index had the highest stroke rate. Former smokers had similar stroke rates to never-smokers. Tests between the associations of risk factors and stroke incidence revealed these were not statistically different from the associations with stroke mortality. CONCLUSIONS: The risk factors had a similar effect on stroke incidence as on stroke mortality. Epidemiological studies with information on stroke mortality are likely to give results applicable to stroke incidence.     

Decreased incidence and mortality of stroke

Dr. Whisnant argues persuasively that control of hypertension has played a major role in the decline of stroke. He offers a cohesive and logical overview on this decline and does so with data from his own vast experience and with the advantages of the Mayo Clinic system which includes a centralized population-based diagnostic index, neurological expertise and a high autopsy rate. However, neither Dr. Whisnant's arguments nor the Mayo Clinic data justify the conclusion that "treatment of hypertension is the only significant contributor to the decline of stroke."