A demonstrated positive effect of a hearing conservation program in the Swedish armed forces

A revised hearing conservation program (HCP) was implemented in the Swedish Armed Forces in 2002. The aim of this study was to evaluate the incidence of significant threshold shifts (STS) in male conscripts heavily exposed to noise after the implementation of the new HCP, comparing the results to those of an earlier study from 1999/2000.

The study was prospective and longitudinal, covering the period from reporting to military service to discharge. The outcome measure was the incidence of STS. Statistics from the military insurance system was analysed.

A total of 395 conscripts were included in the study (mean age 19 years). The control group (n: 839) consisted of men of the same age.

In 2004/2005 the incidence rate of STS was 2.3% compared to 7.9% in 1999/2000 and compared to 3.7% among the controls. The number of cases of auditory complications reported from conscripts to the insurance system has decreased, from 16 to 5/100,000 days of military training, during the last decade.

The new HCP apparently reduced the incidence rate of STS to one third compared to before the program was introduced and leveled it to the incidence rate in the control-group not exposed to military noise.