title: Risk factors associated with vestibular nerve schwannomas.
abstract: BACKGROUND
  Vestibular nerve schwannoma is a benign tumor that originates in the sheath of Schwann of the eighth cranial nerve. It is considered one of the most common benign intracranial tumors, and its cause is unclear.
  
  
  OBJECTIVE
  To identify the risk factors associated with vestibular nerve schwannomas.
  
  
  METHODS
  A hospital-based exploratory case-control study was conducted between 2006 and 2010 in 2 municipalities in the northeast region of Brazil. We included individuals with unilateral vestibular nerve schwannomas confirmed by imaging. The controls, selected from the same institutions as the cases, exhibited unilateral hearing loss or tinnitus and had undergone investigatory examinations similar to those of the cases, but the presence of tumor had been excluded. A pretested structured questionnaire, administered by trained interviewers who were blind to the condition of the individual being interviewed, was used to obtain sociodemographic data and data on potential risk factor exposure. We performed a multivariate analysis using unconditional logistic regression.
  
  
  RESULTS
  A total of 44 patients with vestibular nerve schwannomas and 104 controls participated in the study. A history of chicken pox (odds ratio, 6.59; 95% confidence interval, 2.07-20.9) and the exposure to more than 1 cranial x-ray procedure (odds ratio, 4.55; 95% confidence interval, 1.10-19.2) were identified as potential risk factors.
  
  
  CONCLUSIONS
  This exploratory study brings new hypotheses to be tested and thus works toward clarifying the causes and mechanisms involved in the cause and development of vestibular nerve schwannoma.
authors.affiliation: Department of Hearing and Speech Sciences, Institute of Health Sciences, School of Medicine of Bahia, Federal University of Bahia, Salvador, Brazil. corona@ufba.br
authors.forename: Ana Paula
authors.initials: AP
authors.lastname: Corona
authors.forename: Silvia
authors.initials: S
authors.lastname: Ferrite
authors.forename: Marcia da Silva
authors.initials: Mda S
authors.lastname: Lopes
authors.forename: Marco Antônio Vasconcelos
authors.initials: MA
authors.lastname: Rêgo
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000428:Alcohol Drinking / Q000453:epidemiology; D001938:Brazil / Q000453:epidemiology; D016022:Case-Control Studies; D040421:Cell Phone / Q000706:statistics & numerical data; D002644:Chickenpox / Q000150:complications / Q000453:epidemiology; D006259:Craniocerebral Trauma / Q000150:complications / Q000453:epidemiology; D005260:Female; D006801:Humans; D008019:Life Style; D016015:Logistic Models; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008875:Middle Aged; D009464:Neuroma, Acoustic / Q000150:complications / Q000453:epidemiology*; D009622:Noise / Q000009:adverse effects; D016273:Occupational Exposure / Q000706:statistics & numerical data; D012307:Risk Factors; D018401:Sample Size; D012737:Sex Factors; D012907:Smoking / Q000453:epidemiology; D012959:Socioeconomic Factors; D011795:Surveys and Questionnaires; D014057:Tomography, X-Ray Computed; D014965:X-Rays / Q000009:adverse effects