[Hearing loss of workers in mining--a 6-year longitudinal study]

Area of Science:

• Occupational Health
• Audiology
• Environmental Health

Context:

• Mining environments present significant occupational hazards, including prolonged exposure to high noise levels.
• Simultaneous exposure to noise and vibration is common for miners, potentially influencing auditory health outcomes.
• Understanding the combined effects of noise and vibration is crucial for developing effective hearing protection strategies.

Purpose:

• To determine the hearing threshold level (HTL) in miners after a six-year interval under consistent noise exposure.
• To compare the hearing changes in miners exposed to both noise and vibration versus those exposed only to noise.
• To establish a prognosis for hearing loss extent and the timeline of auditory modifications in miners.

Summary:

• Audiometric examinations were conducted on 132 miners and apprentices over a six-year period.
• Yearly mean rates of hearing threshold changes were calculated based on age and noise exposure duration.
• Miners exposed to both noise and vibration showed yearly decreased HTL values (up to 2000 Hz) compared to noise-only exposed subjects.

Impact:

• The study provides a prognosis indicating that miners with over 21 years of exposure or a mean age of 38 may experience HTL exceeding 30 dB at 4 kHz.
• Findings suggest that vibration exposure, in conjunction with noise, may lead to different hearing threshold level modifications than noise exposure alone.
• This research contributes to understanding the complex relationship between occupational exposures and hearing health in the mining industry.