Study Background
The Problem: NIHL in Construction Workers

Noise-induced hearing loss (NIHL) is among the most common occupational diseases, especially to construction workers. Hearing loss usually progresses unnoticed until it begins to interfere with communication, decreasing quality of life and posing a serious safety hazard, particularly in the construction industry, where audible warning signals are often critical.

Precise exposure-response relationships for NIHL are lacking, especially for the highly variable noise exposures such as are found in construction. In recent years, the potential for distortion product otoacoustic emissions (DPOAEs) as a screening tool for subclinical hearing damage, and possibly as a marker of susceptibility for hearing loss has been recognized. However, no prospective studies of DPOAEs in relation to well-characterized noise exposure and standard audiometry have been conducted.
Study Design
Study subjects (construction apprentices) and controls (UW medical/graduate students) are being monitored for a total of 4 years. Once a year, the following tests are administered to study participants:
  • Audiometry - a standard hearing test to measure the current level of hearing function.
  • DPOAE - a more sensitive hearing test that measures the responsiveness of the ear to certain tones.
  • Tympanometry - a physical examination of the inner ear is performed to assess whether the eardrum is structurally sound.
  • Questionnaire - questionnaires are used to characterize other risk factors for hearing loss, non-occupational exposure to noise, characteristics of work and use of hearing protective devices (HPDs).
  • Noise Dosimetry - noise exposure is monitored once yearly on each subject using data-logging noise dosimeters in conjunction with time/activity cards (a sample card may be viewed). The dosimeters will collect noise levels using 3 and 5 dB exchange rates, as recommended by NIOSH and OSHA, respectively, as well as peak exposure information. These data are being used to develop an activity-exposure matrix to provide estimates of average, peak and variability of exposure during work and home activities.