title: Alcohol consumption and the risk of morbidity and mortality for different stroke types--a systematic review and meta-analysis.
abstract: 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.
authors.affiliation: Centre for Addiction and Mental Health, Toronto, Ontario Canada. jayadeep_patra@camh.net
authors.forename: Jayadeep
authors.initials: J
authors.lastname: Patra
authors.forename: Benjamin
authors.initials: B
authors.lastname: Taylor
authors.forename: Hyacinth
authors.initials: H
authors.lastname: Irving
authors.forename: Michael
authors.initials: M
authors.lastname: Roerecke
authors.forename: Dolly
authors.initials: D
authors.lastname: Baliunas
authors.forename: Satya
authors.initials: S
authors.lastname: Mohapatra
authors.forename: Jürgen
authors.initials: J
authors.lastname: Rehm
mesh_terms: D000428:Alcohol Drinking; D002545:Brain Ischemia / Q000401:mortality* / Q000517:prevention & control; D016022:Case-Control Studies; D015331:Cohort Studies; D005260:Female; D006801:Humans; D020300:Intracranial Hemorrhages / Q000401:mortality* / Q000517:prevention & control; D008297:Male; D009017:Morbidity; D012306:Risk; D020521:Stroke / Q000401:mortality* / Q000517:prevention & control