title: Serum cotinine level and incident hearing loss: a case-control study.
abstract: BACKGROUND
  A growing body of literature suggests an association between cigarette smoking and hearing loss.
  
  
  OBJECTIVE
  To assess the relation between levels of serum cotinine, a biomarker of exposure to tobacco smoke, and incident hearing loss.
  
  
  METHODS
  A cross-sectional, incident, case-control study of participants selected from a population-based cohort.
  
  
  METHODS
  Testing was conducted at the Beaver Dam Community Hospital, Beaver Dam, Wis.
  
  
  METHODS
  A total of 197 participants with incident hearing loss and 394 control participants, aged 53 to 75 years, selected from the 2800 participants of the 5-year follow-up examination of the population-based Epidemiology of Hearing Loss Study, 1998-2000.
  
  
  METHODS
  Incident hearing loss. The incidence of hearing loss was defined as a pure-tone average of thresholds at 500, 1000, 2000, and 4000 Hz greater than 25-dB hearing level in either ear at follow-up among those without hearing loss at baseline.
  
  
  RESULTS
  No significant associations were found between serum cotinine levels and incident hearing loss.
  
  
  CONCLUSIONS
  These results were not consistent with a previous report, which found cross-sectional associations between prevalent hearing loss and current smoking and environmental tobacco smoke exposure in the home. Longer-term longitudinal studies of smoking and/or serum cotinine levels and the subsequent development of hearing loss may help clarify these associations.
authors.affiliation: Department of Ophthalmology and Visual Sciences, The University of Wisconsin-Madison, USA. nondahl@epi.ophth.wisc.edu
authors.forename: David M
authors.initials: DM
authors.lastname: Nondahl
authors.forename: Karen J
authors.initials: KJ
authors.lastname: Cruickshanks
authors.forename: Dayna S
authors.initials: DS
authors.lastname: Dalton
authors.forename: Carla R
authors.initials: CR
authors.lastname: Schubert
authors.forename: Barbara E K
authors.initials: BE
authors.lastname: Klein
authors.forename: Ronald
authors.initials: R
authors.lastname: Klein
authors.forename: Ted S
authors.initials: TS
authors.lastname: Tweed
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001309:Auditory Threshold; D016022:Case-Control Studies; D015986:Confounding Factors, Epidemiologic; D003367:Cotinine / Q000097:blood*; D003430:Cross-Sectional Studies; D015987:Effect Modifier, Epidemiologic; D005260:Female; D034381:Hearing Loss / Q000453:epidemiology*; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D012907:Smoking / Q000453:epidemiology*
chemical_list: D003367:Cotinine