title: Determinants of early-stage hearing loss among a cohort of young workers with 16-year follow-up.
abstract: OBJECTIVE
  The authors had a unique opportunity to study the early impacts of occupational and recreational exposures on the development of noise-induced hearing loss (NIHL) in a cohort of 392 young workers. The objectives of this study were to estimate strength of associations between occupational and recreational exposures and occurrence of early-stage NIHL and to determine the extent to which relationships between specific noise exposures and early-stage NIHL were mitigated through the use of hearing protection.
  
  
  METHODS
  Participants were young adults who agreed to participate in a follow-up of a randomised controlled trial. While the follow-up study was designed to observe long-term effects (up to 16 years) of a hearing conservation intervention for high school students, it also provided opportunity to study the potential aetiology of NIHL in this worker cohort. Study data were collected via exposure history questionnaires and clinical audiometric examinations.
  
  
  RESULTS
  Over the 16-year study period, the authors documented changes to hearing acuity that exceeded 15 dB at high frequencies in 42.8% of men and 27.7% of women. Analyses of risk factors for NIHL were limited to men, who comprised 68% of the cohort, and showed that risks increased in association with higher levels of the most common recreational and occupational noise sources, as well as chemical exposures with ototoxic potential. Use of hearing protection and other safety measures, although not universal and sometimes modest, appeared to offer some protection.
  
  
  CONCLUSIONS
  Early-stage NIHL can be detected in young workers by measuring high-frequency changes in hearing acuity. Hearing conservation programmes should focus on a broader range of exposures, whether in occupational or non-occupational settings. Priority exposures include gunshots, chainsaws, power tools, smoking and potentially some chemical exposures.
authors.affiliation: National Farm Medicine Center, Marshfield Clinic Research Foundation, 1000 North Oak Avenue, Marshfield, WI 54449, USA. marlenga.barbara@mcrf.mfldclin.edu
authors.forename: Barbara
authors.initials: B
authors.lastname: Marlenga
authors.forename: Richard L
authors.initials: RL
authors.lastname: Berg
authors.forename: James G
authors.initials: JG
authors.lastname: Linneman
authors.forename: Douglas J
authors.initials: DJ
authors.lastname: Wood
authors.forename: Steven R
authors.initials: SR
authors.lastname: Kirkhorn
authors.forename: William
authors.initials: W
authors.lastname: Pickett
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D015331:Cohort Studies; D004781:Environmental Exposure / Q000009:adverse effects*; D005260:Female; D005500:Follow-Up Studies; D015386:Hazardous Substances / Q000009:adverse effects; D006317:Hearing Loss, Noise-Induced / Q000453:epidemiology / Q000209:etiology*; D006801:Humans; D008297:Male; D009622:Noise / Q000009:adverse effects*; D009623:Noise, Occupational / Q000009:adverse effects*; D016273:Occupational Exposure / Q000009:adverse effects*; D009790:Occupations; D015995:Prevalence; D011998:Recreation; D012307:Risk Factors; D012737:Sex Factors
chemical_list: D015386:Hazardous Substances