title: Independent risk factors for intracranial aneurysms and their joint effect: a case-control study.
abstract: OBJECTIVE
  Three percent of the population has an unruptured intracranial aneurysm (UIA). We aimed to identify independent risk factors from lifestyle and medical history for the presence of UIAs and to investigate the combined effect of well-established risk factors.
  
  
  METHODS
  We studied 206 patients with an UIA who never had a subarachnoid hemorrhage and 574 controls who were randomly retrieved from general practitioner files. All participants filled in a questionnaire on potential risk factors for UIAs. With logistic regression analysis, we identified independent risk factors for UIA and assessed their combined effect.
  
  
  RESULTS
  Independent risk factors were current smoking (odds ratio [OR], 3.0; 95% confidence interval [CI], 2.0-4.5), hypertension (OR, 2.9; 95% CI, 1.9-4.6), family history of stroke other than subarachnoid hemorrhage (OR, 1.6; 95% CI, 1.0-2.5), hypercholesterolemia (OR, 0.5; 95% CI, 0.3-0.9), and regular physical exercise (OR, 0.6; 95% CI, 0.3-0.9). The joint risk of smoking and hypertension was higher (OR, 8.3; 95% CI, 4.5-15.2) than the sum of the risks independently.
  
  
  CONCLUSIONS
  Current smoking, hypertension, and family history of stroke increase the risk of UIA, with smoking and hypertension having an additive effect, whereas hypercholesterolemia and regular physical exercise decrease this risk. A healthy lifestyle probably reduces the risk of UIA and thereby possibly also that of aneurysmal subarachnoid hemorrhage. Whether smoking and hypertension increase the risk of aneurysmal subarachnoid hemorrhage only through an increased risk of aneurysm formation or also through an increased risk of rupture remains to be established.
authors: Department of Neurology and Neurosurgery, Utrecht Stroke Center, Rudolf Magnus Institute of Neuroscience, University Medical Center, Utrecht, the Netherlands.
authors: Monique H M
authors: MH
authors: Vlak
authors: Gabriel J E
authors: GJ
authors: Rinkel
authors: Paut
authors: P
authors: Greebe
authors: Ale
authors: A
authors: Algra
mesh_terms: D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D006973:Hypertension / Q000175:diagnosis* / Q000473:pathology; D002532:Intracranial Aneurysm / Q000175:diagnosis* / Q000209:etiology*; D008019:Life Style; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D012044:Regression Analysis; D012306:Risk; D012307:Risk Factors; D012907:Smoking; D020521:Stroke; D011795:Surveys and Questionnaires