Risk factors for ischemic stroke: Dubbo Study of the elderly

Effect of subacute and chronic immobilisation stress on the outcome of permanent focal cerebral ischaemia in rats

The aim of this study was to determine the effect of mood disorders, including psychological distress and depression, on stroke outcome. Male Fischer rats were exposed to immobilisation stress, an animal paradigm of psychological stress, major depression and post-traumatic stress disorder. Either a subacute (1 h for 7 days) or a chronic (6 h for 21 days) exposure to stress was applied 24 h before permanent middle cerebral artery occlusion (MCAO). Stroke outcome was assessed by measurement of infarct size and behavioural characterisation. Serum glutamate and brain ATP levels as well as brain glutamate transporter function and expression were studied in the search for the molecular mechanisms involved. Subacute stress exposure increased infarct size and decreased behavioural scores after stroke. On the contrary, chronic stress exposure decreased infarct size. Peak serum glutamate levels correlated with infarct size after MCAO. Expression of glutamate transporters was decreased by subacute stress, whereas the expression of EAAT1, a glial glutamate carrier, was increased after the chronic stress protocol. Our results indicate that distinct patterns of stress determine different stroke outcomes, and that expressional changes of brain glutamate transporters, able to affect glutamate release after stroke, are involved.

The role of lipid profile in determining the risk of ischemic stroke in the elderly: a case-control study

In this study, we investigated the association of lipids with ischemic stroke and its different subtypes in elderly patients. In particular, lipid parameters not extensively investigated so far in previous case-control studies specifically focused in the old population, such as lipoprotein Lp (a) and Apoproteins AI (ApoAI) and B (ApoB), have been taken into account. Seventy nine patients (mean age 83 +/- 7.4, range 67-99), consecutively admitted to a Geriatric Ward between January 1998 and June 2000 with acute stroke (first event) were studied. A complete clinical and laboratory assessment, including neurological evaluation, head CT scan, carotid ultrasonography and ECG, was employed to define the clinical and etiologic stroke subtype, according to standardized criteria. Fasting blood samples were collected within 48 h from admission, for determination of total cholesterol (TC), triglycerides (TG), High Density Lipoprotein-cholesterol (HDL-C), Lp(a), ApoAI and ApoB; Low Density Lipoprotein-Cholesterol (LDL-C) was estimated by Friedwald formula. Eighty eight age and sex-matched outpatients, referred to the hospital for non-inflammatory disorders of joints and musculoskeletal system, served as controls. Patients showed HDL-C and HDL-C/ApoAI ratio significantly lower than controls, with higher LDL-C/HDL-C ratio. Analysis on quartiles of lipoprotein concentrations showed also a significant increase in odds of stroke for LDL-C concentrations over 100 mg/dl, in absence of a linear relationship between LDL-C levels and risk. Multiple logistic regression, adjusting for non-lipid risk factors for stroke, confirmed the independent association of low HDL-C and HDL-C/ApoAI with all strokes, as well as with each subtype. In conclusion, these data suggest that lipids give some contribution to stroke risk even in the elderly, with a more prevalent role for HDL than LDL, and that lipid profile assessment must be taken into account in estimating the individual risk of stroke.

Reduction in serum total cholesterol and risks of coronary events and cerebral infarction in Japanese men: the Kyushu Lipid Intervention Study

Lowering serum total cholesterol is shown to decrease the risk of coronary heart disease (CHD) in Western countries,but evidence is limited regarding cerebral infarction (CI). The present study used the Kyushu Lipid Intervention Study to examine the risks of CHD events and CI in relation to reduction in serum total cholesterol. Subjects were 4,615 men aged 45-74 years with serum total cholesterol of 220 mg/dl (5.68 mmol/L) or greater who had no history of CHD events or stroke. CHD events and CI numbered 125 and 92, respectively, in a 5-year follow-up. After adjustment for potential confounding factors, the relative risks of CHD events and CI for 15% or greater reduction in total cholesterol, compared with less than 5% reduction, were 0.78 (95% confidence limit [CL]0.46-1.32) and 0.39 (95% CL 0.22-0.69), respectively. As compared with on-treatment cholesterol levels of 240 mg/dl (6.20 mmol/L)or higher, the risk of CHD events was approximately 50% lower across 3 categories below 240 mg/dl (6.20 mmol/L), and that of CI was 70%lower at 2 categories below 220 mg/dl (5.68 mmol/L). Lowering serum total cholesterol below 220 mg/dl (5.68 mmol/L) seems desirable with regard to the prevention of CI.

Platelet surface glycoprotein expression in post-stroke depression: a preliminary study

Depression is a significant risk factor for and consequence of both cardiovascular disease and stroke. The pathophysiological processes underlying this association are poorly understood. This study utilised a technique for measurement of whole blood platelet surface glycoproteins involved in early adhesion and aggregation in sample populations of patients with depression and stroke, and healthy controls. We analysed the platelet surface glycoproteins GPIb and GPIIbIIIa using flow cytometry in eight depressed subjects (Hamilton depression score >17), 14 post-stroke subjects (seven depressed and seven non-depressed), and in eight healthy control subjects. The number of GPIb receptors was significantly increased in subjects with depression and in post-stroke subjects compared to control subjects. The number of GPIb receptors from post-stroke subjects was not significantly different from that of depressed subjects. There were no differences between any groups in measures of GPIIbIIIa receptor numbers. No additive effect of co-morbid depression on the surface expression level of either marker could be detected in the post-stroke subjects. Platelet dysfunction may be involved in the pathophysiological process underlying the association between depression and cerebrovascular disease.

Effect of depression on stroke morbidity and mortality

OBJECTIVES

This narrative review examines the evidence and discusses the clinical relevance of depression as a risk factor for stroke morbidity and mortality. It also proposes recommendations for future research.

METHODS

We used the Medline computer database to search the relevant original studies published in English from January 1966 to December 2001. Our key words were as follows: depressive disorder, cerebrovascular disease, stroke, vascular risk factors, and mortality. Articles that investigated the relation between antecedent depression and subsequent stroke morbidity and mortality were collected and reviewed.

RESULTS

Since 1990, 8 prospective studies have been published. Among these 8 studies, 6 addressed depression and stroke morbidity, 1 investigated the association of depression with stroke morbidity and stroke mortality, and 1 investigated the association with stroke mortality only. Of 7 studies examining the independent effect of depression on stroke morbidity, 6 were positive. With regard to stroke mortality, 2 studies found an independent association between depression and specific stroke mortality. The contributions and methodological limitations of these studies are discussed.

CONCLUSIONS

Emerging data suggest an association between depressive symptoms and increased risk for stroke morbidity and mortality. More methodologically sound studies are needed to elucidate causal pathways that link depression and cerebrovascular disease. They are also needed to determine the effect of depression intervention on reducing the risk of cerebrovascular events. Information on author affiliations appears at the end of the article.

Predictors of stroke mortality in elderly people from the general population. The CArdiovascular STudy in the ELderly

Stroke occurs particularly frequently in elderly people and, being more often disabling than fatal, entails a high social burden. The predictors of stroke mortality have been identified in 3282 subjects aged > or = 65 years, taking part in the CArdiovascular STudy in the ELderly (CASTEL), a population-based study performed in Northeast Italy. Historical and clinical data, blood tests and 14-year fatal events were recorded. Continuous items were divided into quintiles and, for each quintile, adjusted relative risk (RR) with 95% confidence intervals [CI] was derived from multivariate Cox analysis. Age, historical stroke (RR: 5.2; 95% CI: 3.18-8.6) and coronary artery disease (RR: 1.38; CI: 1.18-2.1), atrial fibrillation (RR: 2.40; CI: 1.42-4.0), arterial hypertension (RR: 1.33; CI: 1.15-1.76), systolic blood pressure > or = 163 mmHg (RR: 1.84; CI: 1.20-2.59), pulse pressure > or = 74 mmHg (RR: 1.50; CI: 1.13-2.40), cigarette smoking (RR: 1.60; CI: 1.03-2.47), electrocardiographic left ventricular hypertrophy (RR: 1.72; CI: 1.10-2.61), impaired glucose tolerance (IGT, RR: 1.83; CI: 1.10-3.0), uric acid (UA) > 0.38 mmol/l (RR: 1.61; CI: 1.14-2.10), serum potassium > or = 5 mEq/l (RR: 1.70; CI: 1.24-2.50) and serum sodium < or = 139 mEql/l (RR: 1.34; 1.10-2.10) increased the risk of stroke. In the CASTEL, stroke was the first cardiovascular cause of death. Some independent predictors usually unrelated to stroke mortality (namely pulse pressure, pre-diabetic IGT, UA and blood electrolytes disorders) have been identified.

Risk functions for prediction of cardiovascular disease in elderly Australians: the Dubbo Study

OBJECTIVES

To evaluate a Framingham risk function for coronary heart disease in an elderly Australian cohort and to derive a risk function for cardiovascular disease (CVD) in elderly Australians.

DESIGN AND SETTING

Analysis of data from a prospective cohort study (the Dubbo Study) in a semi-urban town (population, 34 000).

PARTICIPANTS

2805 men and women 60 years and older living in the community, first assessed in 1988, and a subcohort of 2102 free of CVD at study entry.

MAIN OUTCOME MEASURES

Incidence of CVD (myocardial infarction, coronary death or stroke) over 5 and 10 years.

RESULTS

A Framingham risk function assessing "hard" coronary heart disease (ie, myocardial infarction or coronary death) accurately predicted 10-year incidence in men and women aged 60-79 years who were free of prevalent CVD or diabetes at study entry. In a multiple logistic model, CVD incidence was significantly predicted by age, sex, taking antihypertensive medication, blood pressure, smoking, total cholesterol level and diabetes. For a given age and cholesterol level, CVD risk over 5 years was doubled in the presence of antihypertensive medication or diabetes, increased by 50% with cigarette smoking, and halved in women compared with men.

CONCLUSIONS

We have derived a simple CVD risk function specifically for elderly Australians that employs risk factors readily accessible to all medical practitioners.

Role of lipid-modifying therapy in the prevention of initial and recurrent stroke

PURPOSE OF REVIEW

To establish the role of cholesterol-modifying therapy in stroke prevention.

RECENT FINDINGS

Population-based observational cohort studies show a variable weak positive relationship between increasing plasma total cholesterol concentrations and an increasing risk of ischaemic stroke, which is partly offset by a weaker negative association between decreasing total cholesterol concentrations and an increasing risk of with haemorrhagic stroke. However, randomized controlled trials show unequivocally that lowering plasma total cholesterol by approximately 1.2 mmol/l (and LDL-cholesterol by 1.0 mmol/l) is associated with a reduced relative risk of stroke and other serious vascular events by at least a quarter, and probably a third, without any increase in haemorrhagic stroke, in a wide range of men and women (including individuals with previous stroke). The proportional reduction in stroke risk is consistent, irrespective of the patient's age, baseline plasma cholesterol concentration, and absolute risk of stroke (although perhaps less in very low-risk individuals), but is increased with greater degrees of cholesterol lowering (15% or more), and thus with statin medications, which are more potent than non-statin interventions in lowering cholesterol levels. The absolute reduction in stroke risk achieved by statins is greatest among individuals at highest risk of stroke. Preliminary evidence suggests that lowering total cholesterol levels by diet may be an effective adjunctive therapy to statins, and raising plasma HDL-cholesterol concentrations among patients with coronary heart disease and low HDL-cholesterol levels ( 1 mmol/l) by means of gemfibrozil may also effectively prevent stroke.

SUMMARY

Statin drugs are effective and safe in preventing initial and recurrent stroke. However, because they are costly, they should probably be restricted to individuals with an annual risk of stroke and other serious vascular events of 3% or greater, and possibly as low as 1.5%, because routine monitoring of plasma cholesterol, and liver and muscle enzyme concentrations is probably no longer necessary.

Insulin resistance: a metabolic link between depressive disorder and atherosclerotic vascular diseases

The association of depression with insulin resistance (IR) and athersclerotic vascular diseases has been well documented. This review examines the relevance of IR as a link between depressive disorder and atherosclerotic vascular diseases. Relevant articles collected from Medline database over the period of 1966-2001 were reviewed. Studies have shown that IR is a state-dependent abnormality in depression and depression increases the risk of vascular morbidity and mortality. Given that IR is a central component of cardiovascular risk factors, depression-related IR might play a role in the development and progression of coronary and cerebral atherosclerosis in chronic-resistant depression. Further, IR may contribute to the pathophysiology of depressive disorder. In conclusion IR could account for the linkage between depression and atherosclerotic vascular diseases. More studies are needed to examine the importance of improving insulin sensitivity in the treatment of chronic-resistant depression and prevention of depression-related vascular morbidity and mortality.

Anatomic location and laterality of MRI signal hyperintensities in late-life depression

OBJECTIVES

Evidence is mounting linking cerebrovascular disease with the development of major depression in the elderly. Lesions in both white and gray matter have been associated with geriatric depression. In addition, the literature on poststroke depression suggests that left-sided lesions are associated with depression. We sought to examine the severity and location of white- and gray-matter lesions in a group of elderly depressives and nondepressed control subjects.

METHOD

115 depressed patients (69 with late onset, 46 with early onset) and 37 controls, all over age 45, received magnetic resonance imaging (MRI). Semiquantitative severity ratings and quantitative measurements of number and size of MRI hyperintensities were obtained, and groups were compared using Cochran-Mantel-Haenszel (CMH) analyses and repeated-measures analyses of covariance adjusting for age.

RESULTS

Late-onset depressed patients had more severe hyperintensity ratings in deep white matter than early-onset patients and controls. Late- and early-onset patients had more severe subcortical gray-matter hyperintensities (particularly in the putamen) compared with controls. Left-sided white-matter lesions were significantly associated with older age of depression onset, whereas right-anterior white matter and left-subcortical lesions (particularly in the putamen) were associated with melancholia in the depressed group.

CONCLUSION

These findings extend previous reports of an association between cerebrovascular disease and depression, as well as recent studies showing lateralized lesion involvement in geriatric depression. Such vascular pathology may disrupt neural pathways involved in affective processing and the maintenance of a normal mood and psychomotor state.

Stroke-related depression

Stroke represents a major health problem in the United States and most European and Asian countries. Depression is probably the most common and serious emotional disorder following stroke. Post-stroke depression (PSD) has frequently been overlooked and left untreated. Prevention of PSD or successful intervention in the early phase may prevent premature deaths as well as facilitate rehabilitation, reduce costs, and improve quality of life. Stroke is clearly a risk factor for depression, and recent evidence suggests that depression increases the risk for stroke, although the mechanisms by which depression leads to stroke remain to be clarified. Once PSD has developed, numerous studies have documented its adverse effect on cognitive recovery, physical recovery, and mortality. Taken together, these studies support the necessity of identifying and treating this condition.

Inequalities in the transition of cerebrovascular disease mortality in New South Wales, Australia 1969-1996

With reference to epidemiological transition theory, this paper examines change in cerebrovascular disease mortality in Australia's most populous state in the 28 year period, 1969-1996. The hypotheses were that in the context of overall stroke mortality decline over the period, marital status, occupational status and spatial differences decreased. However, while overall mortality declined, differentials increased. The reasons for this are considered, with particular implications for epidemiological transition theory and for the targeting of populations at risk in policy terms.

Aging-associated changes in vascular activity: a potential link to geriatric cardiovascular disease

Ischemic cardiovascular disease is a common cause of morbidity and mortality in the United States population over the age of 65. Prior clinical studies have demonstrated that the severity of cardiovascular pathophysiology is increased in older individuals. Both in vitro and in vivo experimental studies have shown that age-associated clinical events parallel changes in vascular function. Aging is associated with systemic as well as cardiac alterations in three basic vascular regulatory functions: vascular tone, hemostasis, and vascular repair/angiogenesis. This article reviews the molecular and cellular events that may contribute to senescent cardiac pathology. Indeed, a better understanding of the biology of aging-associated vascular dysfunction is fundamental for the development of therapeutics targeted for the treatment of cardiovascular disease in older individuals.

Cholesterol and other lipids predict coronary heart disease and ischaemic stroke in the elderly, but only in those below 70 years

The prediction of coronary heart disease (CHD) and stroke by total and low density lipoprotein (LDL) cholesterol in older persons remains problematical. This study tests the hypothesis that cholesterol and other risk factors may be differentially predictive of CHD and ischaemic stroke in older persons when they are segregated into different age groups. CHD and ischaemic stroke outcomes were recorded during 129 months follow-up in a cohort of 2805 men and women of 60 years and older. There were 899 CHD events (32/100) and 326 stroke events (12/100). Using Cox proportional hazards, outcomes were modelled for the total cohort and for age groups 60-69, 70-79, and 80+ years. Total cholesterol, LDL cholesterol, serum apo-B, total cholesterol/high density lipoprotein (HDL) cholesterol and apo-B/apo-A1 were significant predictors of CHD in the total cohort, but significant only in the sub-group of 60-69 years. The respective hazard ratios (CI 95%) were 1.21 (1.09-1.35), 1.21 (1.09-1.35), 1.25 (1.13-1.39), 1.25 (1.14-1.37) and 1.21 (1.10-1.38). Similar findings were applicable with respect to ischaemic stroke in the age group of 60-69 years. Total cholesterol predicted CHD in men above a threshold value of 7.06 mmol/l and in women above 7.8 mmol/l, but with stroke the prediction was incremental. Other risk factors such as HDL cholesterol, triglycerides, lipoprotein(a), diabetes, hypertension and smoking predicted CHD, although only HDL and hypertension similarly predicted ischaemic stroke. The findings support a case for cholesterol testing in older subjects up to 70 years, in whom there is ancillary evidence of CHD and stroke prevention through treatment designed to reduce LDL cholesterol.

A prognostic index for 30-day mortality after stroke

The objective of this study was to develop a simplified scoring system to predict 30-day mortality in patients with acute ischemic stroke. A retrospective cohort study was performed in a tertiary referral hospital in the Hunter Region of Australia. A prognostic index was created by assigning points to the variables in a Cox model. The index included impaired consciousness (5 points), dysphagia (3 points), urinary incontinence (4 points), admission body temperature higher than 36.5 degrees C (2 points), and hyperglycemia without a clinical history of diabetes (2 points). A score of 11 or more defined a high-risk group. The index achieved a sensitivity, specificity, and positive predictive value of 68%, 98% and 75%, respectively, in the derivation sample and 57%, 97% and 68%, respectively, in the validation sample. The results provide a simple risk stratification instrument for clinical research and practice. Further evaluation of the model in a prospective cohort is warranted

The incidence and aetiology of stroke in the Caerphilly and Speedwell Collaborative Studies II: risk factors for ischaemic stroke

Reduction of stroke burden requires preventive interventions targeted at important risk factors. This report presents the analysis of risk factors for ischaemic stroke from a representative cohort of middle aged men from South Wales and south-west England. Data on risk factors were collected through validated questionnaires and physical and clinical measurements. Details of possible cerebrovascular events were retrieved, classified into ischaemic, haemorrhagic and uncertain subtypes, and validated. The ratio of definite ischaemic to definite haemorrhagic strokes was calculated. This showed that the vast majority of strokes of unknown subtype were likely to ischaemic. After exclusion of known haemorrhagic strokes and subarrachnoid haemorrhages the remaining strokes were labelled ischaemic. Hazard ratios for possible risk factors were calculated for all ischaemic, and for fatal and non-fatal strokes. There were 293 ischaemic strokes. Statistically significant age-adjusted hazard ratios were: 1.50 (95% confidence interval 1.16-1.95) for being in a manual social class, 1.82 (1.24-2.67) if smoking >15 cigarettes/d at enrollment, 1.19 (1.13-1.24) and 1.23 (1.14-1.34) per 10 mmHg increase in systolic and diastolic blood pressure, respectively, 0.67 (0.46-0.96) for the top quintile high density lipoprotein-cholesterol:cholesterol ratio compared to the bottom quintile, 2.04 (1.40-2.99) for presence of angina, 3.90 (2.01-7.58) for presence of atrial fibrillation, and 3.35 (1.90-5.80) for presence of diabetes. Risk factors were more strongly associated with fatal than non-fatal strokes. Multivariate analyses revealed that, while there was some attenuation of the effect of social class, angina and elevated BP, the risks from atrial fibrillation and diabetes were increased.

Long-term predictors of stroke in a cohort of people aged 70 years

This paper aims at studying the development and the risk factors for stroke prospectively during a 6-year follow-up in the Turku Elderly Study, Turku, Finland. The study cohort consisted of 1032 people aged 70 years at baseline. The stroke events (ICD-9 codes 430-434) were identified by computer linkage from the hospital discharge and death registers, and from a follow-up questionnaire. During the 6 years of follow-up, 71 patients (6.9%) suffered a stroke. Previous stroke (RR 5.82), history of transient ischemic attack (RR 4.14), diabetes mellitus (RR 2.50), poorly controlled hypertension (RR 2.42), smoking (RR 1.94) and male sex (RR 1.65) were independent risk factors for stroke. Atrial fibrillation, cardiac failure and previous myocardial infarction did not appear to be significant independent predictors of stroke in the elderly. The risk of stroke in the elderly population appears to be strongly related to the concomitant clinical disease, and this should be remembered when identifying persons at increased risk of stroke. Poorly controlled hypertension was associated with an increased risk of stroke. Thus, achieving a good control of blood pressure in elderly hypertensives receiving treatment has the potential to prevent strokes.

Does cholesterol lowering prevent stroke?

The importance of lowering plasma cholesterol to reduce the incidence of coronary events is well established. However, in the prevention of stroke disease, control of hypertension has been the main aim of treatment and lipid lowering therapy has not hitherto been considered to be desirable or necessary. In this review, the evidence from large multicentre trials, imaging studies and meta-analyses is presented. It shows convincingly that HMG-CoA reductase inhibitors (Statins) reduce stroke risk.