Occupational hearing loss in Washington state, 1984-1991: II. Morbidity and associated costs

This study examined 4,547 workers' compensation claims accepted for hearing-related conditions in Washington state between 1984 and 1991; 80% resulted in disability compensation (n = 3,660). Acute hearing-related conditions comprised 11% of accepted conditions (95% confidence interval [CI], 2-15%); most claims were for chronic noise-related hearing loss. Tinnitus was reported in 64% of accepted claims (95% CI, 54-75%). The median binaural-equivalent hearing loss in compensated claims was 12.5% (inter-quartile interval, 5-22%; 90th percentile, 34%), although it declined by 30% during the study period. The number of claims and associated impairment increased with claimant age, but the number of claims dropped dramatically after age 65. Annual total disability settlements almost tripled in 8 years, totaling $22.8 million. This study indicates that occupational hearing-related conditions: 1) are manifested by mild to moderate hearing loss, accompanied by tinnitus in a majority of cases; 2) may be under-recognized in older, formerly noise-exposed individuals; and 3) were associated with substantial increases in compensation and medical costs over time, through 1991.