title: Decreased risk of intracerebral hemorrhage among patients with milder allergic rhinitis.
abstract: BACKGROUND
  This study investigated whether allergic rhinitis (AR) increases the risk of intracerebral hemorrhage (ICH).
  
  
  METHODS
  Using Taiwanese insurance outpatient claims data, 52,870 patients with new diagnoses of AR between 2000 and 2010 were identified, and 105,680 age- and sex-frequency matched people without AR were chosen randomly as controls. Risks of ICH were correlated with AR and comorbidities, such as diabetes, hypertension, coronary artery disease, hyperlipidemia, disease and chronic kidney disease, and were estimated by the end of 2011.
  
  
  RESULTS
  The risk of ICH was lower in the AR cohort than in the comparison cohort, with an adjusted hazard ratio (aHR) of 0.58 (95% confidence interval [CI] = 0.50-0.66), assessed using the multivariable Cox model. Age-specific analysis demonstrated that the aHR for ICH in the AR patients increased with age, with an aHR of 0.53 (95% CI = 0.39-0.71) in the ≤49-year age group, which increased to 0.72 (95% CI = 0.59-0.89) in the elderly age group. The risk of ICH increased with the severity of AR, from an aHR of 0.47 (95% CI = 0.40-0.56) in mild AR patients to 2.55 (95% CI = 1.88-3.47) in severe ones. For patients without comorbidities, the risk of ICH was 0.46 times (95% CI = 0.34-0.63) lower in the AR cohort than in the comparison cohort.
  
  
  CONCLUSIONS
  This study showed for the first time that milder AR is correlated with a reduction in the risk of ICH, particularly for elderly patients.
authors.affiliation: From the Department of Neurology, China Medical University Hospital, School of Medicine, China Medical University College of Medicine.
authors.forename: C-H
authors.initials: CH
authors.lastname: Tseng
authors.affiliation: School of Medicine, China Medical University College of Medicine, Department of Internal Medicine, China Medical University Hospital.
authors.forename: J-H
authors.initials: JH
authors.lastname: Chen
authors.affiliation: School of Medicine, China Medical University College of Medicine, Management Office for Health Data, China Medical University Hospital.
authors.forename: C-L
authors.initials: CL
authors.lastname: Lin
authors.affiliation: Graduate Institute of Clinical Medical Science and School of Medicine, College of Medicine, China Medical University and Department of Nuclear Medicine and PET Center, China Medical University Hospital, Taichung, Taiwan d10040@mail.cmuh.org.tw.
authors.forename: C-H
authors.initials: CH
authors.lastname: Kao
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D016022:Case-Control Studies; D002543:Cerebral Hemorrhage / Q000453:epidemiology* / Q000517:prevention & control; D015897:Comorbidity; D005260:Female; D006801:Humans; D015994:Incidence; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D065631:Rhinitis, Allergic / Q000453:epidemiology*; D012307:Risk Factors; D013624:Taiwan / Q000453:epidemiology