title: Comparison of two dose-response relationship of noise exposure evaluation results with high frequency hearing loss.
abstract: BACKGROUND
  Complex noise and its relation to hearing loss are difficult to measure and evaluate. In complex noise measurement, individual exposure results may not accurately represent lifetime noise exposure. Thus, the mean L Aeq,8 h values of individuals in the same workgroup were also used to represent L Aeq,8 h in our study. Our study aimed to explore whether the mean exposure levels of workers in the same workgroup represented real noise exposure better than individual exposure levels did.
  
  
  METHODS
  A cross-sectional study was conducted to establish a model for cumulative noise exposure (CNE) and hearing loss in 205 occupational noise-exposed workers who were recruited from two large automobile manufacturers in China. We used a personal noise dosimeter and a questionnaire to determine the workers' occupational noise exposure levels and exposure times, respectively. A qualified audiologist used standardized audiometric procedures to assess hearing acuity after at least 16 h of noise avoidance.
  
  
  RESULTS
  We observed that 88.3% of workers were exposed to more than 85 dB(A) of occupational noise (mean: 89.3 ± 4.2 dB(A)). The personal CNE (CNEp) and workgroup CNE (CNEg) were 100.5 ± 4.7 dB(A) and 100.5 ± 2.9 dB(A), respectively. In the binary logistic regression analysis, we established a regression model with high-frequency hearing loss as the dependent variable and CNE as the independent variable. The Wald value was 5.014 with CNEp as the independent variable and 8.653 with CNEg as the independent variable. Furthermore, we found that the figure for CNEg was more similar to the stationary noise reference than CNEp was. The CNEg model was better than the CNEp model. In this circumstance, we can measure some subjects instead of the whole workgroup and save manpower.
  
  
  CONCLUSIONS
  In a complex noise environment, the measurements of average noise exposure level of the workgroup can improve the accuracy and save manpower.
authors.forename: Hua
authors.initials: H
authors.lastname: Zhang
authors.forename: Nan
authors.initials: N
authors.lastname: Li
authors.forename: Qiu-Ling
authors.initials: QL
authors.lastname: Yang
authors.forename: Wei
authors.initials: W
authors.lastname: Qiu
authors.forename: Liang-Liang
authors.initials: LL
authors.lastname: Zhu
authors.forename: Li-Yuan
authors.initials: LY
authors.lastname: Tao
authors.forename: Robert I
authors.initials: RI
authors.lastname: Davis
authors.forename: Nicholas
authors.initials: N
authors.lastname: Heyer
authors.affiliation: Research Center of Clinical Epidemiology, Peking University Third Hospital, Beijing 100191, China.
authors.forename: Yi-Ming
authors.initials: YM
authors.lastname: Zhao
mesh_terms: D000328:Adult; D003430:Cross-Sectional Studies; D005260:Female; D006316:Hearing Loss, High-Frequency / Q000175:diagnosis* / Q000209:etiology*; D006801:Humans; D008297:Male; D009622:Noise / Q000009:adverse effects; D009623:Noise, Occupational / Q000009:adverse effects*; D016273:Occupational Exposure / Q000009:adverse effects