title: The effects of smoking and alcohol consumption on age-related hearing loss: the Blue Mountains Hearing Study.
abstract: OBJECTIVE
  We aimed to investigate the temporal association between smoking or alcohol consumption and hearing loss, and to confirm previously published cross-sectional associations.
  
  
  METHODS
  The Blue Mountains Hearing Study is a population-based survey of age-related hearing loss conducted in a defined suburban area, west of Sydney. Hearing loss was measured in 2956 participants (aged 50+ yrs) and was defined as the pure-tone average of frequencies 0.5, 1.0, 2.0, and 4.0 kHz >25 dB HL in the better ear (bilateral hearing loss). Alcohol consumption and smoking status were measured using an interviewer-administered questionnaire. Logistic regression was used to obtain odds ratios (OR) with 95% confidence intervals (95% CI) that compared the chances of having hearing loss in participants who did or did not smoke or consume alcohol, after adjusting for other factors previously reported to be associated with hearing loss.
  
  
  RESULTS
  The prevalence of hearing loss at baseline was 33.0% (N = 929) and the 5-year incidence of hearing loss was 17.9% (N = 156). Cross-sectional analysis demonstrated a significant protective association between the moderate consumption of alcohol (>1 but < or =2 drinks/day) and hearing function in older adults (compared with nondrinkers), OR 0.75 (95% CI, 0.57 to 0.98). Current smokers not exposed to occupational noise had a significantly higher likelihood of hearing loss after adjusting for multiple variables, OR 1.63 (95% CI, 1.01 to 2.64). A formal likelihood ratio test demonstrated that the interaction between smoking and noise exposure was not significant (p = 0.23). When the joint effects of alcohol consumption and smoking on hearing were explored, there was a trend for alcohol to have a protective relationship with hearing loss in smokers, but this was not statistically significant. However, the 5-year incidence of hearing loss was not predicted by either smoking or alcohol consumption.
  
  
  CONCLUSIONS
  This study confirms previously reported associations between alcohol consumption or smoking and prevalent hearing loss, but these were not demonstrated in temporal data. Other risk factors could confer greater vulnerability or cause the initial damage to hearing. Future large population-based studies, exploring the influence of other risk factors on the development of age-related hearing loss are warranted.
authors.affiliation: Centre for Vision Research, Department of Ophthalmology, Westmead Millennium Institute, University of Sydney, NSW, Australia.
authors.forename: B
authors.initials: B
authors.lastname: Gopinath
authors.forename: V M
authors.initials: VM
authors.lastname: Flood
authors.forename: C M
authors.initials: CM
authors.lastname: McMahon
authors.forename: G
authors.initials: G
authors.lastname: Burlutsky
authors.forename: W
authors.initials: W
authors.lastname: Smith
authors.forename: P
authors.initials: P
authors.lastname: Mitchell
mesh_terms: D000368:Aged; D000428:Alcohol Drinking / Q000453:epidemiology*; D003430:Cross-Sectional Studies; D005260:Female; D006312:Hearing Loss, Bilateral / Q000453:epidemiology*; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009517:New South Wales / Q000453:epidemiology; D009623:Noise, Occupational / Q000706:statistics & numerical data; D011304:Presbycusis / Q000453:epidemiology*; D015995:Prevalence; D012307:Risk Factors; D012907:Smoking / Q000453:epidemiology*; D013383:Suburban Population / Q000706:statistics & numerical data*