title: Active and passive smoking and the risk of subarachnoid hemorrhage: an international population-based case-control study.
abstract: OBJECTIVE
  This study was undertaken to better clarify the risks associated with cigarette smoking and subarachnoid hemorrhage (SAH).
  
  
  METHODS
  The study included 432 incident cases of SAH frequency matched to 473 community SAH-free controls to determine dose-dependent associations of active and passive smoking (at home) and smoking cessation with SAH.
  
  
  RESULTS
  Compared with never smokers not exposed to passive smoking, the adjusted odds ratio for SAH among current smokers was 5.0 (95% confidence interval [CI], 3.1 to 8.1); for past smokers, 1.2 (95% CI, 0.8 to 2.0); and for passive smokers, 0.9 (95% CI, 0.6 to 1.5). Current and lifetime exposures showed a clear dose-dependent effect, and risks appeared more prominent in women and for aneurysmal SAH. Approximately 1 in 3 cases of SAH could be attributed to current smoking, but risks decline quickly after smoking cessation, even among heavy smokers.
  
  
  CONCLUSIONS
  A strong positive association was found between cigarette smoking and SAH, especially for aneurysmal SAH and women, which is virtually eliminated within a few years of smoking cessation. Large opportunities exist for preventing SAH through smoking avoidance and cessation programs.
authors.affiliation: Clinical Trials Research Unit, University of Auckland, Private Bag 92019, Auckland, New Zealand. c.anderson@ctru.auckland.ac.nz
authors.forename: Craig S
authors.initials: CS
authors.lastname: Anderson
authors.forename: Valery
authors.initials: V
authors.lastname: Feigin
authors.forename: Derrick
authors.initials: D
authors.lastname: Bennett
authors.forename: Ruey-Bin
authors.initials: RB
authors.lastname: Lin
authors.forename: Graeme
authors.initials: G
authors.lastname: Hankey
authors.forename: Konrad
authors.initials: K
authors.lastname: Jamrozik
mesh_terms: D001315:Australia / Q000453:epidemiology; D016022:Case-Control Studies; D015897:Comorbidity; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009520:New Zealand / Q000453:epidemiology; D016017:Odds Ratio; D018570:Risk Assessment; D012307:Risk Factors; D012737:Sex Factors; D012907:Smoking / Q000453:epidemiology*; D016540:Smoking Cessation / Q000706:statistics & numerical data; D013345:Subarachnoid Hemorrhage / Q000453:epidemiology*; D014028:Tobacco Smoke Pollution / Q000706:statistics & numerical data*
chemical_list: D014028:Tobacco Smoke Pollution