The prevalence of noise-induced hearing loss in seamen.

Hearing was analysed in 231 seamen with the length of sea service longer than five years. Among 107 seamen in deck service, 86 seamen in engine service, and 38 seamen in radio and general services statistically significant differences in relation to age, total length of service and the length of sea service were not established. There were no differences in the degree of hearing loss among those groups of seamen either. Based upon calculated simple regression coefficients, a statistically significant correlation was established between age, total length of service or length of sea service with the average hearing loss at the frequencies of 500, 1000, 2000 and 4000 Hz in the left ear in seamen from all ship services. Correlation was best pronounced at 2000 and 4000 Hz. In seamen from deck, radio or general services, a significant multiple correlation was established between age, total length of service and length of sea service, and the degree of hearing loss at 4000 Hz in the left ear. The same correlation, likewise, was true of seamen from deck service at 2000 Hz in the left ear and at 4000 Hz in the right ear.