title: Risk factors for fatal subarachnoid hemorrhage: the Japan Collaborative Cohort Study.
abstract: OBJECTIVE
  The present study aimed to identify risk factors for mortality due to subarachnoid hemorrhage (SAH) using a comprehensive questionnaire from the Japan Collaborative Cohort (JACC) Study, a Japan-wide population-based prospective study.
  
  
  METHODS
  A total of 109,293 individuals (45,551 men and 63,742 women, aged 40 to 79 years) free of stroke at entry participated in the JACC Study between 1988 and 1990. Participants were followed up annually until they died or moved away from the surveyed community, or until the end of 1999. A diagnosis of death from SAH was based on the International Classification of Diseases, 10th revision (ICD-10). The age-adjusted univariate and multivariate hazard ratios (HR) and 95% confidence intervals (CI) of various factors were calculated in sex-stratified and sex-specific analyses using the Cox proportional hazards regression model.
  
  
  RESULTS
  A total of 244 individuals (88 men and 156 women) died from SAH during the follow-up of 1 086 963 person-years. Our univariate analyses confirmed that preference for salty foods and history of blood transfusion, as well as hypertension, family history of stroke, cigarette smoking, heavy alcohol consumption, and low BMI, had statistically significant associations with mortality due to SAH. Multivariable analyses revealed that history of blood transfusion was an independent significant risk factor (HR=4.2 [95%CI, 2.1 to 8.5]) for men, while preference for salty foods or heavy drinking were not.
  
  
  CONCLUSIONS
  History of blood transfusion was found to be an independent risk. The association between SAH and blood transfusion warranted further study.
authors.affiliation: Dept of Health and Environmental Sciences, Graduate School of Medicine Kyoto University, Konoe-cho, Yoshida, Sakyo-ku, Kyoto, 606-8501, Japan.
authors.forename: Shigeki
authors.initials: S
authors.lastname: Yamada
authors.forename: Akio
authors.initials: A
authors.lastname: Koizumi
authors.forename: Hiroyasu
authors.initials: H
authors.lastname: Iso
authors.forename: Yasuhiko
authors.initials: Y
authors.lastname: Wada
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Watanabe
authors.forename: Chigusa
authors.initials: C
authors.lastname: Date
authors.forename: Akio
authors.initials: A
authors.lastname: Yamamoto
authors.forename: Shogo
authors.initials: S
authors.lastname: Kikuchi
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Inaba
authors.forename: Hideaki
authors.initials: H
authors.lastname: Toyoshima
authors.forename: Takaaki
authors.initials: T
authors.lastname: Kondo
authors.forename: Akiko
authors.initials: A
authors.lastname: Tamakoshi
mesh_terms: D000328:Adult; D017677:Age Distribution; D000368:Aged; D001803:Blood Transfusion / Q000706:statistics & numerical data; D015331:Cohort Studies; D015897:Comorbidity; D003299:Cooperative Behavior; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012307:Risk Factors; D017678:Sex Distribution; D012907:Smoking / Q000009:adverse effects / Q000453:epidemiology; D013345:Subarachnoid Hemorrhage / Q000401:mortality*; D011795:Surveys and Questionnaires; D065227:Transfusion Reaction