title: Prevalence of noise induced hearing loss among employees at a mining industry in Zimbabwe.
abstract: BACKGROUND
  Noise induced hearing loss (NIHL) is within the top five occupational illnesses in Zimbabwe. Workers at a mining company complained about loss of hearing at the mine clinic.
  
  
  OBJECTIVE
  To determine the prevalence of NIHL among employees at the Mine.
  
  
  METHODS
  We conducted a descriptive cross sectional study at the mine. Workers were proportionally selected to represent all the mine departments or working areas. We measured noise levels at various mine sites, conducted a walk-through survey to observe noise related worker practices and conducted audiometric testing.
  
  
  RESULTS
  Mean age for workers was 34.8±7.6 years and the mean duration of exposure to noise was 7.5±1.2 years. All workers could define noise. Ninety (53%) workers attributed NIHL to noisy work environment. Excessive noise levels were in Plant Processing (94 dBA), Underground Mining (102 dBA) and (Underground Workshop (103 dBA). Sixty two (36.7%) workers had NIHL. NIHL increased as a function of age (chi square=30.99 df=3 p<0.01) and was associated with work area (chi square=24.96 df=5 p<0.01). Observed workers took heed of noise warnings. There was no documented hearing conservation program at the mine.
  
  
  CONCLUSIONS
  The prevalence of NIHL of 37% is high. Age and work area were associated with NIHL. Studies reported that age tends to distort the relationship between noise exposure and NIHL. Mine management should institute a hearing conservation program to protect employees against hazardous noise. Management may meanwhile use administrative controls and adhere to permissible exposure limits according to the noise regulations.
authors.affiliation: Department of Community Medicine, University of Zimbabwe.
authors.forename: A
authors.initials: A
authors.lastname: Chadambuka
authors.affiliation: Department of Community Medicine, University of Zimbabwe.
authors.forename: F
authors.initials: F
authors.lastname: Mususa
authors.affiliation: Department of Community Medicine, University of Zimbabwe.
authors.forename: S
authors.initials: S
authors.lastname: Muteti
mesh_terms: D000328:Adult; D003430:Cross-Sectional Studies; D005260:Female; D006317:Hearing Loss, Noise-Induced / Q000453:epidemiology*; D006320:Hearing Tests; D006801:Humans; D007407:Interviews as Topic; D008297:Male; D008875:Middle Aged; D008906:Mining; D009623:Noise, Occupational / Q000009:adverse effects*; D009784:Occupational Diseases / Q000453:epidemiology* / Q000209:etiology; D016273:Occupational Exposure; D011159:Population Surveillance; D015995:Prevalence; D036301:Qualitative Research; D015030:Zimbabwe / Q000453:epidemiology