Alcohol and stroke: a community case-control study in Asturias, Spain

Cerebral Hemorrhage and Alcohol Exposure: A Review

Aims

To investigate the dose–response relationships between alcohol and intracerebral hemorrhage (ICH), the impact of alcohol on the outcome of ICH and possible mechanisms underlying hypertensive ICH (HICH) caused by heavy drinking.

Methods

Literature search from 1985 to August 2019 in the PubMed database.

Results

The relationship between low-middle alcohol consumption and ICH remains controversial for various reasons, whereas chronic heavy drinking increases the incidence of ICH and exerts worse outcome. More attention is needed to clarify the characteristics of chronic alcohol intake and binge drinking. Chronic alcohol abuse tends to elevates blood pressure, resulting in increased occurrence of HICH and exaggerated HICH-contributed brain injury.

Conclusion

It is important to develop strategies to promote reasonable intake categories, prevent alcoholism and thus reduce the risk of ICH.

Alcohol use and risk of intracerebral hemorrhage

OBJECTIVE

To analyze the dose-risk relationship for alcohol consumption and intracerebral hemorrhage (ICH) in the Ethnic/Racial Variations of Intracerebral Hemorrhage (ERICH) study.

METHODS

ERICH is a multicenter, prospective, case-control study, designed to recruit 1,000 non-Hispanic white patients, 1,000 non-Hispanic black patients, and 1,000 Hispanic patients with ICH. Cases were matched 1:1 to ICH-free controls by age, sex, race/ethnicity, and geographic area. Comprehensive interviews included questions regarding alcohol consumption. Patterns of alcohol consumption were categorized as none, rare (<1 drink per month), moderate (≥1 drink per month and ≤2 drinks per day), intermediate (>2 drinks per day and <5 drinks per day), and heavy (≥5 drinks per day). ICH risk was calculated using the no-alcohol use category as the reference group.

RESULTS

Multivariable analyses demonstrated an ordinal trend for alcohol consumption: rare (odds ratio [OR] 0.57, p < 0.0001), moderate (OR 0.65, p < 0.0001), intermediate (OR 0.82, p = 0.2666), and heavy alcohol consumption (OR 1.77, p = 0.0003). Subgroup analyses demonstrated an association of rare and moderate alcohol consumption with decreased risk of both lobar and nonlobar ICH. Heavy alcohol consumption demonstrated a strong association with increased nonlobar ICH risk (OR 2.04, p = 0.0003). Heavy alcohol consumption was associated with significant increase in nonlobar ICH risk in black (OR 2.34, p = 0.0140) and Hispanic participants (OR 12.32, p < 0.0001). A similar association was not found in white participants.

CONCLUSIONS

This study demonstrated potential protective effects of rare and moderate alcohol consumption on ICH risk. Heavy alcohol consumption was associated with increased ICH risk. Race/ethnicity was a significant factor in alcohol-associated ICH risk; heavy alcohol consumption in black and Hispanic participants poses significant nonlobar ICH risk.

Low-Dose Ethanol Preconditioning Protects Against Oxygen-Glucose Deprivation/Reoxygenation-Induced Neuronal Injury By Activating Large Conductance, Ca2+-Activated K+ Channels In Vitro

Increasing evidence suggests that low to moderate ethanol ingestion protects against the deleterious effects of subsequent ischemia/reperfusion; however, the underlying mechanism has not been elucidated. In the present study, we showed that expression of the neuronal large-conductance, Ca²⁺-activated K⁺ channel (BK_Ca) α-subunit was upregulated in cultured neurons exposed to oxygen-glucose deprivation/reoxygenation (OGD/R) compared with controls. Preconditioning with low-dose ethanol (10 mmol/L) increased cell survival rate in neurons subjected to OGD/R, attenuated the OGD/R-induced elevation of cytosolic Ca²⁺ levels, and reduced the number of apoptotic neurons. Western blots revealed that ethanol preconditioning upregulated expression of the anti-apoptotic protein Bcl-2 and downregulated the pro-apoptotic protein Bax. The protective effect of ethanol preconditioning was antagonized by a BK_Ca channel inhibitor, paxilline. Inside-out patches in primary neurons also demonstrated the direct activation of the BK_Ca channel by 10 mmol/L ethanol. The above results indicated that low-dose ethanol preconditioning exerts its neuroprotective effects by attenuating the elevation of cytosolic Ca²⁺ and preventing neuronal apoptosis, and this is mediated by BK_Ca channel activation.

Beyond Ischemic Heart Disease: Are There other Health Benefits from Drinking Alcohol?

Evidence is growing that alcohol consumption confers health benefits beyond protection from ischemic heart disease. We review this evidence with regard to cerebrovascular disease, peripheral vascular disease, diabetes, cholelithiasis (gallstones), cognitive functioning, and stress reduction and subjective psychosocial benefits. Other possible benefits are briefly considered. The weight of evidence suggests that low-level alcohol consumption offers some protection against ischemic stroke. The evidence that moderate alcohol consumption protects against diabetes and gallstones is also fairly strong. The possibility of other health benefits cannot be dismissed. For all the conditions considered, more research is indicated. The application of more appropriate statistical techniques, studies of patterns of drinking, and experimental approaches to delineating underlying mechanisms should enable firmer conclusions to be drawn. A better understanding of both the benefits and the risks of alcohol use for individuals and populations will facilitate the development of appropriate program and policy interventions to promote health.

Moderate alcohol intake reduces risk of ischemic stroke in Korea

OBJECTIVE

We undertook a population-based, case-control study to examine a dose-response relationship between alcohol intake and risk of ischemic stroke in Koreans who had different alcoholic beverage type preferences than Western populations and to examine the effect modifications by sex and ischemic stroke subtypes.

METHODS

Cases (n = 1,848) were recruited from patients aged 20 years or older with first-ever ischemic stroke. Stroke-free controls (n = 3,589) were from the fourth and fifth Korean National Health and Nutrition Examination Survey and were matched to the cases by age (±3 years), sex, and education level. All participants completed an interview using a structured questionnaire about alcohol intake.

RESULTS

Light to moderate alcohol intake, 3 or 4 drinks (1 drink = 10 g ethanol) per day, was significantly associated with a lower odds of ischemic stroke after adjusting for potential confounders (no drinks: reference; <1 drink: odds ratio 0.38, 95% confidence interval 0.32-0.45; 1-2 drinks: 0.45, 0.36-0.57; and 3-4 drinks: 0.54, 0.39-0.74). The threshold of alcohol effect in women was slightly lower than that in men (up to 1-2 drinks in women vs up to 3-4 drinks in men), but this difference was not statistically significant. There was no statistical interaction between alcohol intake and the subtypes of ischemic stroke (p = 0.50). The most frequently used alcoholic beverage was one native to Korea, soju (78% of the cases), a distilled beverage with 20% ethanol by volume.

CONCLUSIONS

Our findings suggest that light to moderate distilled alcohol consumption may reduce the risk of ischemic stroke in Koreans.

Effects of Chronic Alcohol Exposure on the Modulation of Ischemia-Induced Glutamate Release via Cannabinoid Receptors in the Dorsal Hippocampus

BACKGROUND

Chronic alcohol consumption is a critical contributing factor to ischemic stroke, as it enhances ischemia-induced glutamate release, leading to more severe excitotoxicity and brain damage. But the neural mechanisms underlying this phenomenon are poorly understood.

METHODS

We evaluated the effects of chronic alcohol exposure on the modulation of ischemia-induced glutamate release via CB1 and CB2 cannabinoid receptors during middle cerebral artery occlusion, using in vivo microdialysis coupled with high-performance liquid chromatography, in alcohol-naïve rats or rats after 1 or 30 days of withdrawal from chronic ethanol intake (6% v/v for 14 days).

RESULTS

Intra-dorsal hippocampus (DH) infusions of ACEA or JWH133, selective CB1 or CB2 receptor agonists, respectively, decreased glutamate release in the DH in alcohol-naïve rats in a dose-dependent manner. Such an effect was reversed by co-infusions of SR141716A or AM630, selective CB1 or CB2 receptor antagonists, respectively. After 30 days, but not 1 day of withdrawal, ischemia induced an enhancement in glutamate release in the DH, as compared with non-alcohol-treated control group. Intra-DH infusions of JWH133, but not ACEA, inhibited ischemia-induced glutamate release in the DH after 30 days of withdrawal. Finally, 1 day of withdrawal did not alter the protein level of CB1 or CB2 receptors in the DH, as compared to non-alcohol-treated control rats. Whereas 30 days of withdrawal robustly decreased the protein level of CB1 receptors, but failed to alter the protein level of CB2 receptors, in the DH, as compared to non-alcohol-treated control rats.

CONCLUSIONS

Together, these findings suggest that loss of expression/function of CB1 receptors, but not CB2 receptors in the DH, is correlated with the enhancement of ischemia-induced glutamate release after prolonged alcohol withdrawal.

Heavy ethanol consumption aggravates the ischemic cerebral injury by inhibiting ALDH2

BACKGROUND

Heavy ethanol consumption is widely accepted as a risk for ischemic stroke. The molecular mechanisms of ethanol-induced brain injury have not been fully understood.

AIM

This study aims to find out the mechanism of the ischemic cerebral injury.

METHODS

We used Sprague-Dawley rats with transient middle cerebral artery occlusion for acute experiment and stroke-prone spontaneously hypertensive rats for long-term experiment in vivo, and oxygen-glucose deprivation model in vitro to define a detrimental effect of different doses of ethanol on ischemic stroke injury. We also used mitochondrial aldehyde dehydrogenase 2 knockdown/overexpression or inhibitor/activator to investigate mechanism of the adverse effects of ethanol.

RESULTS

High-dose ethanol (36% of calorie derived from ethanol) significantly increased the infarct size in rats (P < 0·01) and decreased the survival time of stroke-prone spontaneously hypertensive rats by about 20%. Six-week treatment with high-dose ethanol changed a distribution of isoelectric point of aldehyde dehydrogenase 2 and inhibited aldehyde dehydrogenase 2 activity in brain. High dose of ethanol increased the cerebral acetaldehyde level, and increased 4-hydroxy-2-nonenal and malondialdehyde in serum of rats with middle cerebral artery occlusion. The activator of aldehyde dehydrogenase 2, Alda-1 abolished neuronal cells death and ischemic injury induced by ethanol and the inhibitor reversed the injurious effects. An overexpression of aldehyde dehydrogenase 2 completely abolished the increased infarct size and neurological deficit score by ethanol. Conversely, knockdown of aldehyde dehydrogenase 2 increased the infarct size and exaggerated the cerebral injury induced by ethanol.

CONCLUSIONS

High concentrations of ethanol aggravate cerebral injury by inhibiting of aldehyde dehydrogenase 2 and inducing excess accumulation of aldehydes.

Vascular endothelial growth factor and monocyte chemoattractant protein-1 levels unaltered in symptomatic atherosclerotic carotid plaque patients from north India

We aimed to identify the role of vascular endothelial growth factor (VEGF) and monocyte chemoattractant protein (MCP-1) as a serum biomarker of symptomatic carotid atherosclerotic plaque in North Indian population. Individuals with symptomatic carotid atherosclerotic plaque have high risk of ischemic stroke. Previous studies from western countries have shown an association between VEGF and MCP-1 levels and the incidence of ischemic stroke. In this study, venous blood from 110 human subjects was collected, 57 blood samples of which were obtained from patients with carotid plaques, 38 neurological controls without carotid plaques, and another 15 healthy controls who had no history of serious illness. Serum VEGF and MCP-1 levels were measured using commercially available enzyme-linked immunosorbent assay. We also correlated the data clinically and carried out risk factor analysis based on the detailed questionnaire obtained from each patient. For risk factor analysis, a total of 70 symptomatic carotid plaque cases and equal number of age and sex matched healthy controls were analyzed. We found that serum VEGF levels in carotid plaque patients did not show any significant change when compared to either of the controls. Similarly, there was no significant upregulation of MCP-1 in the serum of these patients. The risk factor analysis revealed that hypertension, diabetes, and physical inactivity were the main correlates of carotid atherosclerosis (p < 0.05). Prevalence of patients was higher residing in urban areas as compared to rural region. We also found that patients coming from mountain region were relatively less vulnerable to cerebral atherosclerosis as compared to the ones residing at non mountain region. On the contrary, smoking, obesity, dyslipidemia, alcohol consumption, and tobacco chewing were not observed as the determinants of carotid atherosclerosis risk in North India (p > 0.05). We conclude that the pathogenesis of carotid plaques may progress independent of these inflammatory molecules. In parallel, risk factor analysis indicates hypertension, diabetes, and sedentary lifestyle as the most significant risk factors of ischemic stroke identified in North India. This could be helpful in early identification of subjects at risk for stroke and devising health care strategies.

Dose-related influence of chronic alcohol consumption on cerebral ischemia/reperfusion injury

BACKGROUND

We examined the dose-related influence of alcohol consumption on cerebral ischemia/reperfusion (I/R) injury and the potential mechanism that accounts for the disparate effects of high-dose and low-dose alcohol consumption on cerebral I/R injury.

METHODS

Sprague-Dawley rats were fed a liquid diet with or without 1, 3, 5, or 6.4% (v/v) alcohol for 8 weeks and subjected to a 2-hour middle cerebral artery occlusion (MCAO). We evaluated the brain injury at 24 hours of reperfusion. In addition, we measured protein expression of NMDA receptor and excitatory amino acid transporters (EAATs) in parietal cortex and the effect of NMDA receptor antagonist, memantine, on 2-hour MCAO/24 h reperfusion-induced brain injury.

RESULTS

Compared with non-alcohol-fed rats, the total infarct volume was not altered in 3 and 5% alcohol-fed rats but significantly reduced in 1% alcohol-fed rats and exacerbated in 6.4% alcohol-fed rats. Expression of the NMDA receptor subunit, NR1, was upregulated in 6.4% alcohol-fed rats, whereas expression of EAAT2 was downregulated in 6.4% alcohol-fed rats and upregulated in 1% alcohol-fed rats. Memantine reduced 2-hour MCAO/24 h reperfusion-induced brain injury in non-alcohol-fed and 6.4% alcohol-fed rats, but not in 1% alcohol-fed rats. The magnitude of reduction in the brain injury was greater in 6.4% alcohol-fed rats compared to non-alcohol-fed rats.

CONCLUSIONS

Our findings suggest that chronic consumption of low-dose alcohol protects the brain against I/R injury, whereas chronic consumption of high-dose alcohol has detrimental effect on cerebral I/R injury. The disparate effects of low-dose and high-dose alcohol consumption on cerebral I/R may be related to an alteration in NMDA excitotoxicity.

Alcohol consumption and the risk of morbidity and mortality for different stroke types--a systematic review and meta-analysis

BACKGROUND

Observational studies have suggested a complex relationship between alcohol consumption and stroke, dependent on sex, type of stroke and outcome (morbidity vs. mortality). We undertook a systematic review and a meta-analysis of studies assessing the association between levels of average alcohol consumption and relative risks of ischemic and hemorrhagic strokes separately by sex and outcome. This meta-analysis is the first to explicitly separate morbidity and mortality of alcohol-attributable stroke and thus has implications for public health and prevention.

METHODS

Using Medical Subject Headings (alcohol drinking, ethanol, cerebrovascular accident, cerebrovascular disorders, and intracranial embolism and thrombosis and the key word stroke), a literature search of MEDLINE, EMBASE, CINAHL, CABS, WHOlist, SIGLE, ETOH, and Web of Science databases between 1980 to June 2009 was performed followed by manual searches of bibliographies of key retrieved articles. From twenty-six observational studies (cohort or case-control) with ischemic or hemorrhagic strokes the relative risk or odds ratios or hazard ratios of stroke associated with alcohol consumption were reported; alcohol consumption was quantified; and life time abstention (manually estimated where data for current abstainers were given) was used as the reference group. Two reviewers independently extracted the information on study design, participant characteristics, level of alcohol consumption, stroke outcome, control for potential confounding factors, risk estimates and key criteria of study quality using a standardized protocol.

RESULTS

The dose-response relationship for hemorrhagic stroke had monotonically increasing risk for increasing consumption, whereas ischemic stroke showed a curvilinear relationship, with a protective effect of alcohol for low to moderate consumption, and increased risk for higher exposure. For more than 3 drinks on average/day, in general women had higher risks than men, and the risks for mortality were higher compared to the risks for morbidity.

CONCLUSIONS

These results indicate that heavy alcohol consumption increases the relative risk of any stroke while light or moderate alcohol consumption may be protective against ischemic stroke. Preventive measures that should be initiated are discussed.

Effect of chronic alcohol consumption on brain damage following transient focal ischemia

Chronic alcohol consumption impairs cerebral vasoreactivity, and thus, may result in an increase in ischemic brain damage. The goal of this study is to examine the influence of chronic alcohol consumption on transient focal ischemia-induced brain damage. Sprague-Dawley rats were divided into two groups, a control group and an alcohol group. Eight weeks after being fed a liquid diet with or without alcohol, responses of parietal pial arterioles to systemic hypoxia and hypercapnia were measured using a cranial window technique. In separate experiments, rats were subjected to right middle cerebral artery occlusion (MCAO) for 2 h under ketamine/xylazine or isoflurane anesthesia. Regional cerebral blood flow (rCBF) was monitored through a Laser-Doppler flow probe attached to the lateral aspect of the skull. Neurological evaluation and ischemic lesion were assessed 24 h after reperfusion. Dilation of pial arterioles in response to hypoxia and hypercapnia was significantly reduced in alcohol-fed rats. Alcohol-fed rats had significantly larger infarct volumes and worse neurological outcomes than non-alcohol-fed rats under ketamine/xylazine or isoflurane anesthesia. In addition, rCBF measurement indicated that alcohol-fed rats had less regulatory rebound increase in rCBF after the initial drop in rCBF at the onset of MCAO. Our findings suggest that chronic alcohol consumption exacerbates transient focal ischemia-induced brain damage. Increased ischemic brain damage during alcohol consumption may be related to an impaired cerebral vasoreactivity.

Increased risk of cerebral hemorrhage in Chinese male heavy drinkers with mild liver disorder

BACKGROUND

Epidemiological evidence suggests that heavy alcohol consumption increases the risk for either stroke or liver disease. The goal of this study was to determine whether heavy drinkers with mild liver disorder (MLD) are at risk of hemorrhagic stroke.

METHODS

All of the 524 patients recruited were males with a first-ever acute stroke and were consecutively admitted to the Tri-Service General Hospital between January 2000 and December 2001. The risk factors, liver function, stroke subtypes, and hemostatic factors were assessed among 68 patients defined as heavy drinker stroke (HDS) and 456 patients as non-heavy drinker stroke (NHDS).

RESULTS

HDS patients had a significantly higher incidence of hemorrhagic stroke than NHDS patients. HDS patients were also associated with significantly higher occurrence of cigarette smoking, hyperuricemia, liver dysfunction, and significantly lower platelet counts. HDS patients with MLD were more likely to have hemorrhagic stroke (76.5%) than HDS patients without MLD (33.3%) and NHDS patients with (40.3%) or without (26.7%) MLD. HDS patients with MLD also exhibited a significantly higher glutamic oxaloacetic transaminase/glutamic pyruvic transaminase ratio (2.0 +/- 1.2) and lower platelet number (185,000 +/- 85,000 per microl) when compared with HDS patients without MLD (1.4 +/- 0.5; 206,000 +/- 59,000 per microl) and NHDS patients with (1.1 +/- 1.0; 256,000 +/- 97,000 per microl) or without (1.4 +/- 0.7; 216,000 +/- 68,000 per microl) MLD.

CONCLUSIONS

HDS patients with MLD are at higher risk for hemorrhagic stroke in part due to the changes in hemostatic factors, although other factors may also contribute to hemorrhagic stroke.

Interaction Between Alcohol and Exercise

Alcohol use, particularly excessive alcohol consumption is one of the most serious health risks in the world. A relationship between sport, exercise and alcohol consumption is clear and long-standing. Alcohol continues to be the most frequently consumed drug among athletes and habitual exercisers and alcohol-related problems appear to be more common in these individuals. Alcohol use is directly linked to the rate of injury sustained in sport events and appears to evoke detrimental effects on exercise performance capacity. The model of alcohol consumption in human experimental studies has either been acute (single dose) or chronic (repeated doses over a period). These studies suggested that alcohol consumption decreases the use of glucose and amino acids by skeletal muscles, adversely affects energy supply and impairs the metabolic process during exercise. In addition, chronic alcohol use is associated with increased citrate synthase activity and decreased cross-sectional area of type I, IIa and IIb fibres. There is evidence to suggest that exercise may attenuate the ethanol-induced decline in hepatic mitochondria and accelerates ethanol metabolism by the liver. Exercise training seems to reduce the extent of the oxidative damage caused by ethanol. Evidence generated from in vitro experiments and animal studies have also suggested that ethanol administration decreased skeletal muscle capillarity and increased pyruvate kinase and lactate dehydrogenase activities. Substantial epidemiological evidence has been accrued showing that moderate ingestion of alcohol may reduce the incidence of cardiovascular diseases. Although the existing evidence is often confusing and disparate, one of the mechanisms by which alcohol may reduce the incidence of mortality of cardiovascular diseases is through raising levels of high-density lipoprotein cholesterol. Available evidence suggests that exercise and moderate alcohol consumption may have favourable effects on blood coagulation and fibrinolysis; however, compelling experimental evidence is lacking to endorse this notion. Occasional and chronic alcohol consumption is usually linked with unfavourable alterations in platelet aggregation and function and may be associated with platelet-related thrombus formation. Although the effects of alcohol consumption on the rheological properties of the blood are not known, recent experimental evidence suggests that alcohol use following exercise is associated with unfavourable changes in the main determinants of blood viscosity. It is well documented that alcohol use modulates the immune system and impairs host defence. Compelling evidence is also mounting to suggest that chronic alcohol use is linked with adverse effects on the body systems and organs including the brain, the cardiovascular system and the liver.

Inward Rectifier Potassium Channels in the Basilar Artery During Chronic Alcohol Consumption

BACKGROUND

The goals of this study were to determine whether chronic alcohol consumption alters potassium channel-mediated reactivity in the basilar artery and to determine a potential mechanism that might account for the effects of alcohol on the basilar artery.

METHODS

Sprague-Dawley rats were fed liquid diets with or without alcohol for 2 to 3 months. We measured diameter of the basilar artery in response to potassium channel inhibitors and activators. Protein level of inward rectifier potassium channel subunit Kir2.1 in the basilar artery was determined by Western blot.

RESULTS

Topical application of glibenclamide (1 and 10 microM) significantly constricted the basilar artery at high dose; iberiotoxin (10 and 100 nM), 4-AP (0.1 and 1 mM), and BaCl2 (1 and 10 microM) produced dose-related constriction in both non-alcohol-fed and alcohol-fed rats. However, the magnitude of constriction in response to BaCl2 was significantly less in alcohol-fed rats compared with non-alcohol-fed rats. Topical application of KCl (1 and 3 mM), cromakalim (0.1 and 0.3 microM), and NS1619 (10 and 30 microM) induced dose-related dilation in non-alcohol-fed and alcohol-fed rats. However, the magnitude of vasodilation in response to KCl was significantly less in alcohol-fed rats compared with non-alcohol-fed rats. In addition, Kir2.1 protein level in the basilar artery was significantly reduced in alcohol-fed compared with non-alcohol-fed rats.

CONCLUSIONS

These findings suggest that chronic alcohol consumption reduces expression of inward rectifier potassium channels and inhibits KIR channel-mediated dilation in the basilar artery.

Food habits are associated with lipid peroxidation in an elderly population

OBJECTIVE

The purpose of this study was to assess the association between dietary intake and lipid peroxidation.

DESIGN

Cross-sectional population analysis from an ongoing prospective study. Malondialdehyde (MDA) was measured as a marker of lipid peroxidation. Diet was assessed through direct observation and food frequency questionnaire.

SUBJECTS

Participants with no missing data were 162 nonsmoking elderly individuals residing in 7 institutions across Asturias (Spain).

STATISTICAL ANALYSES PERFORMED

Comparisons of adjusted group means by tertiles of plasma MDA were made by analysis of variance. Stepwise regression analysis was done using MDA as a dependent variable and food intake as an independent variable. Food intakes were categorized into quartiles and logistic regression was applied to calculate the odds ratio for being in the highest tertile of plasma MDA.

RESULTS

Consumption of potatoes had an independent direct effect and accounted for a sizeable proportion of the variation in plasma MDA levels (18%, P<.001). In addition to potatoes, other foods that had an apparently independent effect on plasma MDA were eggs, cooked vegetables, and red wine (R(2)=0.028, 0.023 and 0.018, respectively). In this study, dietary factors accounted for 25% of the variation in plasma MDA levels.

CONCLUSION

Identifying nutritional determinants of oxidative stress is important because of its negative health effect. Consumption of cooked vegetables and moderate intake of wine has been shown to be appropriate for reducing the risk of oxidative damage. On the contrary, caution must be used with the intake of potatoes because we have found a positive association with MDA levels. Further studies are required to investigate the mechanism(s) of this association and whether it is related to the preparation method or to the potato itself.

Risk factors for intracerebral hemorrhage in the general population: a systematic review

BACKGROUND AND PURPOSE

Although data on some risk factors for intracerebral hemorrhage (ICH) already are beyond doubt, for other factors, the evidence is less clear. We performed a systematic overview of case-control and cohort studies on risk factors for ICH.

METHODS

We searched MEDLINE, LILACS, EXTRAMED, and Pascal from 1966 to 2001 to identify studies. Studies were included if they met predefined methodological criteria. When possible, 2x2 tables were extracted and combined with the Mantel-Haenszel method. Summary odds ratios (ORs) were calculated for case-control studies, and summary relative risks (RRs) were found for cohort studies and for case-control and cohort studies combined.

RESULTS

Fourteen case-control and 11 cohort studies were identified. We could not always combine the results of case-control and cohort studies. In cohort studies, the crude RR for age (every 10-year increase) was 1.97 (95% confidence interval [CI], 1.79 to 2.16). In case-control studies, the crude OR for high alcohol intake was 3.36 (95% CI, 2.21 to 5.12) and for hypertension was 3.68 (95% CI, 2.52 to 5.38). Two cohort studies showed an increasing risk of ICH with increasing degree of hypertension. In cohort and case-control studies combined, the crude RR for sex (male versus female) was 3.73 (95% CI, 3.28 to 4.25); for current smoking, 1.31 (95% CI, 1.09 to 1.58); and for diabetes, 1.30 (95% CI, 1.02 to 1.67).

CONCLUSIONS

Risk factors for ICH appeared to be age, male sex, hypertension, and high alcohol intake. High cholesterol tends to be associated with a lower risk of ICH. We could not assess whether these risk factors are independent.

Alcohol consumption and risk of stroke: a meta-analysis

CONTEXT

Observational studies suggest that heavy alcohol consumption may increase the risk of stroke while moderate consumption may decrease the risk.

OBJECTIVE

To examine the association between alcohol consumption and relative risk of stroke.

DATA SOURCES

Studies published in English-language journals were retrieved by searching MEDLINE (1966-April 2002) using Medical Subject Headings alcohol drinking, ethanol, cerebrovascular accident, cerebrovascular disorders, and intracranial embolism and thrombosis and the key word stroke; Dissertation Abstracts Online using the keywords stroke and alcohol; and bibliographies of retrieved articles.

STUDY SELECTION

From 122 relevant retrieved reports, 35 observational studies (cohort or case control) in which total stroke, ischemic stroke, or hemorrhagic (intracerebral or total) stroke was an end point; the relative risk or relative odds and their variance (or data to calculate them) of stroke associated with alcohol consumption were reported; alcohol consumption was quantified; and abstainers served as the reference group.

DATA EXTRACTION

Information on study design, participant characteristics, level of alcohol consumption, stroke outcome, control for potential confounding factors, and risk estimates was abstracted independently by 3 investigators using a standardized protocol.

DATA SYNTHESIS

A random-effects model and meta-regression analysis were used to pool data from individual studies. Compared with abstainers, consumption of more than 60 g of alcohol per day was associated with an increased relative risk of total stroke, 1.64 (95% confidence interval [CI], 1.39-1.93); ischemic stroke, 1.69 (95% CI, 1.34-2.15); and hemorrhagic stroke, 2.18 (95% CI, 1.48-3.20), while consumption of less than 12 g/d was associated with a reduced relative risk of total stroke, 0.83 (95%, CI, 0.75-0.91) and ischemic stroke, 0.80 (95% CI, 0.67-0.96), and consumption of 12 to 24 g/d was associated with a reduced relative risk of ischemic stroke, 0.72 (95%, CI, 0.57-0.91). The meta-regression analysis revealed a significant nonlinear relationship between alcohol consumption and total and ischemic stroke and a linear relationship between alcohol consumption and hemorrhagic stroke.

CONCLUSIONS

These results indicate that heavy alcohol consumption increases the relative risk of stroke while light or moderate alcohol consumption may be protective against total and ischemic stroke.

Trends in community knowledge of the warning signs and risk factors for stroke

CONTEXT

Poor public knowledge of stroke warning signs and risk factors limits effective stroke intervention and prevention.

OBJECTIVE

To examine temporal trends in public knowledge of stroke warning signs and risk factors.

DESIGN AND SETTING

Population-based random-digit telephone survey conducted in July-November 2000 among individuals in the greater Cincinnati, Ohio, region.

PARTICIPANTS

A total of 2173 survey respondents (69% response rate) were randomly identified based on their demographic similarities to the ischemic stroke population with regard to age, race, and sex.

MAIN OUTCOME MEASURES

Spontaneous recall of at least 1 important stroke warning sign and 1 established stroke risk factor in comparison with findings from the same survey in 1995.

RESULTS

In 2000, 70% of respondents correctly named at least 1 established stroke warning sign vs 57% in 1995 (P<.001), and 72% correctly named at least 1 established stroke risk factor vs 68% in 1995. Groups of individuals with the highest risk and incidence of stroke, such as persons at least 75 years old, blacks, and men, were the least knowledgeable about warning signs and risk factors. Television was the most frequently cited source of knowledge, 32% in 2000 vs 24% in 1995 (P<.001).

CONCLUSIONS

Public knowledge of stroke warning signs within the greater Cincinnati region has significantly improved from 1995 to 2000, although knowledge of stroke risk factors did not improve significantly during the same time period. Public education efforts must continue and should focus on groups at the highest risk of stroke.

Spontaneous intracerebral hemorrhage: epidemiology and clinical presentation

The advent of widespread CT availability has dramatically changed our understanding of the incidence and risk factors regarding intracerebral hemorrhage (ICH). In the pre-CT era, many patients with a small ICH were misclassified having had ischemic strokes and patients with massive ICH or subarachnoid hemorrhage (SAH) were often difficult to classify correctly. The fact that the precise mechanism of spontaneous ICH is often difficult to ascertain without pathologic evidence continues to hamper epidemiologic studies. This article reviews the incidence rates, natural history, epidemiology, and clinical presentations of nontraumatic ICH.

Stroke: a review with an African perspective

The frequency of stroke and stroke-associated mortality are higher in Blacks than in other races. Several of the known risk factors for stroke, such as hypertension, diabetes and obesity, are more common in Blacks than Whites, and sickle-cell disease and HIV infection are stroke risk factors with particular relevance to Africans. Although the facilities for accurate stroke diagnosis and classification are unavailable in most parts of Africa, careful analysis of the clinical features can minimize the rates of misdiagnosis and misclassification. The high levels of stroke-attributable morbidity and mortality observed in Africans could be markedly reduced by instituting primary and secondary preventive measures and by educating health-care professionals on stroke-management strategies.

Effect of alcohol on lipids and lipoproteins in relation to atherosclerosis

Several studies indicate that light-to-moderate alcohol consumption is associated with a low prevalence of coronary heart disease. An increase in high-density lipoprotein (HDL) cholesterol is associated with alcohol intake and appears to account for approximately half of alcohol's cardioprotective effect. In addition to changes in the concentration and composition of lipoproteins, alcohol consumption may alter the activities of plasma proteins and enzymes involved in lipoprotein metabolism: cholesteryl ester transfer protein, phospholipid transfer protein, lecithin:cholesterol acyltransferase, lipoprotein lipase, hepatic lipase, paraoxonase-1 and phospholipases. Alcohol intake also results in modifications of lipoprotein particles: low sialic acid content in apolipoprotein components of lipoprotein particles (e.g., HDL apo E and apo J) and acetaldehyde modification of apolipoproteins. In addition, "abnormal" lipids, phosphatidylethanol, and fatty acid ethyl esters formed in the presence of ethanol are associated with lipoproteins in plasma. The effects of lipoproteins on the vascular wall cells (endothelial cells, smooth muscle cells, and monocyte/macrophages) may be modulated by ethanol and the alterations further enhanced by modified lipids. The present review discusses the effects of alcohol on lipoproteins in cholesterol transport, as well as the novel effects of lipoproteins on vascular wall cells.

Temporal effect of alcohol consumption on reactivity of pial arterioles: role of oxygen radicals

Chronic alcohol consumption reduces nitric oxide synthase-dependent responses of pial arterioles via mechanisms that remain uncertain. In addition, the temporal effects of alcohol on pial arterioles is unclear. Thus our goals were to examine the role of oxygen-derived free radicals in alcohol-induced impairment of cerebrovascular reactivity and the temporal effect of alcohol on reactivity of pial arterioles. Sprague-Dawley rats were pair-fed a liquid diet with or without alcohol for 2-3 wk, 2-3 mo, or 5-6 mo. We measured the in vivo diameter of pial arterioles in response to nitric oxide synthase-dependent dilators acetylcholine and ADP and the nitric oxide synthase-independent dilator nitroglycerin. In nonalcohol-fed rats, acetylcholine (1.0 and 10 microM) and ADP (10 and 100 microM) produced dose-related dilatation of pial arterioles. Whereas there was no difference in reactivity of arterioles to the agonists in rats fed the nonalcohol and alcohol diets for a period of 2-3 wk, there was a significant impairment in reactivity of arterioles to acetylcholine and ADP, but not nitroglycerin, in rats fed the alcohol diet for longer durations. We then found that treatment with superoxide dismutase did not alter baseline diameter of pial arterioles in nonalcohol-fed or alcohol-fed rats, but significantly improved impaired nitric oxide synthase-dependent dilatation of pial arterioles in alcohol-fed rats. Thus our findings suggest a temporal relationship in the effects of alcohol on reactivity of pial arterioles and that impaired nitric oxide synthase-dependent cerebral vasodilatation during chronic alcohol consumption may be related, in part, to enhanced release of oxygen-derived free radicals.

Superoxide dismutase ameliorates impaired nitric oxide synthase-dependent dilatation of the basilar artery during chronic alcohol consumption

The goals of this study were to determine whether chronic alcohol consumption impairs nitric oxide synthase-dependent reactivity of the basilar artery and to determine a potential mechanism which might account for the effects of alcohol on the basilar artery. Sprague-Dawley rats were fed liquid diets with or without alcohol for 8 weeks. Using intravital microscopy, we measured the diameter of basilar artery in response to nitric oxide synthase-dependent agonists (acetylcholine and bradykinin) and a nitric oxide synthase-independent agonist (nitroglycerin). Topical application of acetylcholine (0.1 and 1 microM) and bradykinin (1 and 10 nM) produced dose-related dilatation of the basilar artery in non-alcohol-fed and alcohol-fed rats. However, the magnitude of vasodilatation in response to acetylcholine and bradykinin was significantly less in alcohol-fed rats compared to non-alcohol-fed rats. Dilatation of the basilar artery in response to nitroglycerin was similar in non-alcohol-fed and alcohol-fed rats. Next, we examined whether impaired responses of the basilar artery in alcohol-fed rats in response to acetylcholine and bradykinin may be related to the production of oxygen radicals. We found that topical application of superoxide dismutase (150 U/ml) significantly improved impaired receptor-mediated nitric oxide synthase-dependent dilatation of basilar artery in alcohol-fed rats. However, superoxide dismutase did not alter responses of the basilar artery to nitroglycerin in alcohol-fed rats, and did not alter responses of the basilar artery to nitric oxide synthase-dependent or -independent agonists in non-alcohol-fed rats. Our findings suggest that chronic consumption of alcohol impairs nitric oxide synthase-dependent dilatation of a large cerebral artery which may be related to the receptor-mediated release of oxygen radicals to inactivate nitric oxide.

Alcohol intake, type of beverage, and the risk of cerebral infarction in young women

BACKGROUND AND PURPOSE

The relationship between alcohol consumption and cerebral infarction remains uncertain, and few studies have investigated whether the relationship varies by alcohol type or is present in young adults. We examined the relationship between alcohol consumption, beverage type, and ischemic stroke in the Stroke Prevention in Young Women Study.

METHODS

All 59 hospitals in the greater Baltimore-Washington area participated in a population-based case-control study of stroke in young women. Case patients (n=224) were aged 15 to 44 years with a first cerebral infarction, and control subjects (n=392), identified by random-digit dialing, were frequency matched by age and region of residence. The interview assessed lifetime alcohol consumption and consumption and beverage type in the previous year, week, and day. ORs were obtained from logistic regression models controlling for age, race, education, and smoking status, with never drinkers as the referent.

RESULTS

Alcohol consumption, up to 24 g/d, in the past year was associated with fewer ischemic strokes (<12 g/d: OR 0.57, 95% CI 0. 38 to 0.86; 12 to 24 g/d: OR 0.38, 95% CI 0.17 to 0.86; >24 g/d: OR 0.95, 95% CI 0.43 to 2.10) in comparison to never drinking. Analyses of beverage type (beer, wine, liquor) indicated a protective effect for wine consumption in the previous year (<12 g/wk: OR 0.58, 95% CI 0.35 to 0.97; 12 g/wk to <12 g/d: OR 0.55, 95% CI 0.28 to 1.10; >/=12 g/d: OR 0.92, 95% CI 0.23 to 3.64).

CONCLUSIONS

Light to moderate alcohol consumption appears to be associated with a reduced risk of ischemic stroke in young women.

Effect of acute alcohol on ischemia-induced glutamate release and brain damage

Epidemiological studies show that chronic ethanol consumption at high doses enhances the risk of cerebral stroke. The mechanisms responsible for the greater vulnerability of alcoholics' brains to stroke have to be completely understood, but a role for excitatory amino acids has been suggested. In order to study the interaction between alcohol and ischemia, we investigated the effect of acute alcohol administration in a model of focal cerebral ischemia. In particular, we evaluated the release of glutamate and aspartate from the cerebral frontal cortex by a transdialysis technique. Alcohol was acutely administered at 1.5 and 3.0 g/kg ip. During the period of maximal alcoholemia, ethanol almost abolished the ischemia-induced release of glutamate leading to glutamate values around or below the basal. Aspartate levels were unaltered both following ischemia and alcohol+ischemia. The decrease in glutamate release, however, was not accompanied by a significant reduction of the extension of the damaged area assessed by histological analysis.