Hearing loss starts early in construction work

A new study shows construction workers begin sustaining long-term hearing damage in their first three years of work.

US researchers recruited subjects from eight construction trades (carpenters, cement workers, electricians, ironworkers, insulation workers, masonry workers, operating engineers and sheet metal workers) shortly after their apprentice training commenced. Control subjects were recruited from among first year doctoral and medical school students, to ensure a comparable age distribution.

The researchers used the distortion product otoacoustic emissions (DPOAEs) measurement system to assess hearing loss. This method involves measuring the intensity of sound emanating from the inner ear using a microphone probe placed in the ear canal.

The apprentices and students were tested over three years, and the study found that small but significant decrements over time in DPOAEs were evident among the construction trades.

The magnitude of the change - about -0.5 dB a year - was smaller than expected but was nonetheless indicative of the potentially long-term damage effect of noise on hearing, the researchers said.

Average exposure levels for the apprentices were between 85 and 90 dB, but the researchers said it is possible that the highly intermittent exposures found in the construction industry produce a different course of hearing damage than would continuous exposures.

The researchers said their study highlights the need for effective hearing protection programs, and that DPOAEs may have potential surveillance applications.

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