EFFECTS OF NOISE EXPOSURE, RACE, AND YEARS OF SERVICE ON HEARING IN US ARMY SOLDIERS

Over the last two decades the U.S. Army has instituted a comprehensive hearing conservation program (HCP) to reduce the prevalence of hearin g loss in soldiers and civilian employees. As a component of this prog ram, hearing threshold levels (HTLs) are stored in a central computeri zed Army-wide hearing conservation data registry. The aim of this stud y was to analyze the hearing threshold data to compare the hearing los s among soldiers representing different (1) race groups, (2) noise exp osure groups, and (3) durations of military service. HTLs were age-cor rected using data base B values from ISO 1999 (1990). As may be expect ed, soldiers exposed to high noise levels had significantly poorer hea ring than the group of soldiers with limited noise exposure. On the av erage, results indicated a significant difference in HTLs among the ra ce groups with black soldiers having the most sensitive hearing and wh ite soldiers having the poorest. Also, subjects with greater durations of military service had the least sensitive hearing. Finally, race an d years of service factors were found to interact in their effect on H TL. The findings are discussed in terms of implications of race differ ences, normative data, and effectiveness of the U.S. Army HCP.