title: Auditory threshold, phonologic demand, and incident dementia.
abstract: OBJECTIVE
  This study was undertaken to investigate the association of auditory threshold with cognitive decline and dementia.
  
  
  METHODS
  The 1,057 surviving men of the Caerphilly cohort with audiometric data at baseline were followed for 17 years for cognitive outcomes. Pure-tone unaided audiometric threshold was assessed at 0.5, 1, 2, and 4 KHz at baseline and after 9 years. Incident dementia was assessed according to DSM-IV criteria, including standard criteria for vascular dementia and for Alzheimer disease. Cognitive decline was assessed by repeat administration of a cognitive test battery.
  
  
  RESULTS
  Mean age-adjusted auditory threshold across both time points was associated with incident dementia and cognitive decline. After adjustment for premorbid cognitive function, the association with dementia was retained (odds ratio(0.5 KHz) = 2.67; 95% confidence interval, 1.38-5.18; p = 0.004). Stronger associations with cognitive decline were found for tests administered by interview than for those administered by computer.
  
  
  CONCLUSIONS
  This study has found an association of auditory threshold with dementia and cognitive decline over a 17-year period. The mechanisms underlying this association are unclear and may include a prodromal effect of dementia on auditory threshold, an effect of auditory threshold on cognitive assessment, an effect of auditory threshold on cognitive loss, or a shared etiologic pathway between both.
authors.affiliation: Institute of Primary Care and Public Health, Cardiff University, Cardiff, Wales, UK. Gallacher@cf.ac.uk
authors.forename: John
authors.initials: J
authors.lastname: Gallacher
authors.forename: Victor
authors.initials: V
authors.lastname: Ilubaera
authors.forename: Yoav
authors.initials: Y
authors.lastname: Ben-Shlomo
authors.forename: Antony
authors.initials: A
authors.lastname: Bayer
authors.forename: Mark
authors.initials: M
authors.lastname: Fish
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Babisch
authors.forename: Peter
authors.initials: P
authors.lastname: Elwood
mesh_terms: D001301:Audiometry, Pure-Tone; D001309:Auditory Threshold / Q000502:physiology*; D003072:Cognition Disorders / Q000453:epidemiology* / Q000503:physiopathology; D003704:Dementia / Q000453:epidemiology* / Q000503:physiopathology; D006801:Humans; D015994:Incidence; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D012307:Risk Factors