title: Differences in aneurysm and patient characteristics between cohorts of Finnish and Dutch patients with subarachnoid hemorrhage: time trends between 1986 and 2005.
abstract: OBJECTIVE
  The high incidence of aneurysmal subarachnoid hemorrhage (aSAH) in Finland may be related to genetic or environmental factors, which may also influence patient and aneurysm characteristics. We compared these characteristics in 2 cohorts in Finland (Kuopio) and the Netherlands (Utrecht).
  
  
  METHODS
  For aSAH patients in Kuopio (n=1786) and Utrecht (n=1788), we compared sex, age at onset, and the sites and number of aneurysms from 1986 to 2005. Five-year time trends were assessed with chi(2) tests (sex distribution and the sites and number of aneurysms) and with 1-way ANOVA (age).
  
  
  RESULTS
  The proportion of men in Kuopio (46.1%; 95% CI, 43.8% to 48.4%) was higher than in Utrecht (33.6%, 95% CI, 31.4% to 35.8%) and declined in Kuopio from 50.9% (95% CI, 46.3% to 55.5%) in 1986-1990 to 42.8% (95% CI, 38.0% to 47.6%) in 2001-2005. Mean+/-SD age at onset was 52.4+/-13.3 years in Kuopio and 53.3+/-14.3 years in Utrecht. Both increased similarly over time. The most common aneurysm site in the Kuopio cohort was the middle cerebral artery (33.1%; 95% CI, 30.9% to 35.3%) and in the Utrecht cohort was the anterior communicating artery (38.0%; 95% CI, 35.5% to 40.5%). Multiple aneurysms were more frequent in Kuopio (27.8%; 95% CI, 25.1% to 29.2%) than in Utrecht (14.8%; 95% CI, 13.0% to 16.6%). Sites and proportions of multiple aneurysms did not change during 1986-2005.
  
  
  CONCLUSIONS
  The cohorts of aSAH patients differed with respect to age at onset and the number and sites of aneurysms. The decline in the proportion of men in Kuopio coincided with increased smoking and alcohol use in women and decreased smoking in men. The differences in aneurysm characteristics remained stable, which suggests that these factors are less influenced by environmental factors.
authors.affiliation: Department of Neurology, Rudolf Magnus Institute of Neuroscience, University Medical Centre Utrecht, GA Utrecht, The Netherlands. C.E.P.vanMunster@umcutrecht.nl
authors.forename: Caspar E P
authors.initials: CE
authors.lastname: van Munster
authors.forename: Mikael
authors.initials: M
authors.lastname: von und zu Fraunberg
authors.forename: Gabriel J E
authors.initials: GJ
authors.lastname: Rinkel
authors.forename: Jaako
authors.initials: J
authors.lastname: Rinne
authors.forename: Timo
authors.initials: T
authors.lastname: Koivisto
authors.forename: Antti
authors.initials: A
authors.lastname: Ronkainen
mesh_terms: D000328:Adult; D017668:Age of Onset; D000368:Aged; D000428:Alcohol Drinking / Q000453:epidemiology; D017542:Aneurysm, Ruptured / Q000453:epidemiology; D015331:Cohort Studies; D005260:Female; D005387:Finland / Q000453:epidemiology; D006801:Humans; D015994:Incidence; D002532:Intracranial Aneurysm / Q000150:complications / Q000453:epidemiology*; D008297:Male; D008875:Middle Aged; D009017:Morbidity / Q000639:trends; D009426:Netherlands / Q000453:epidemiology; D011446:Prospective Studies; D017678:Sex Distribution; D012907:Smoking / Q000453:epidemiology; D013345:Subarachnoid Hemorrhage / Q000453:epidemiology* / Q000209:etiology