This study evaluated the risk to hearing health associated with duty on the flight deck of a Nimitz class aircraft carrier. Descriptive data includes time-weighted average noise exposure and an evaluation of temporary threshold shift for a group of nonaviator flight deck personnel (FD), and a comparison of accrued permanent threshold shift among three shipboard occupational groups that had been matched for years of military service. The study participants included 76 FD personnel in a high-exposure group, 77 engineers in a moderate-exposure group, and 52 administrative personnel who were considered to have low occupational noise exposure. The study found a mean FD time weighted average of 109 dBA over workdays averaging 11.5 hours. Only 2 (4%) of 52 administrative personnel had any appreciable hearing loss (defined as worse than 20 dB at any frequency 1,000 through 4,000 Hz), whereas FD and engineers demonstrated 17% and 27% hearing impairment, respectively.

This study presents mean hearing thresholds from a cross-sectional study of 68,632 monitoring audiograms submitted to the Navy Environmental Health Center for 1995 to 1999. Records included U.S. Navy and U.S. Marine Corps enlisted personnel (Navy men = 51,643; Navy women = 4,184; Marine Corps men = 12,251: Marine Corps women = 554). Mean hearing thresholds were calculated for age groups (17-24, 25-29, 30-34, 35-39, 40-44, 45-49, and 50 years and older), gender (male/female), and service (Navy/Marine Corps). Although hearing thresholds worsened with increasing age, as expected, Navy and Marine Corps men have worse levels than Occupational Safety and Health Administration age-corrected values throughout most of their careers, whereas women were closer to the Occupational Safety and Health Administration values. Hearing thresholds in the Navy have not improved appreciably from historical reports. Threshold variability, as revealed by standard deviations, increased with age and paralleled threshold levels. This epidemiological information suggests that hearing conservation continues to be an important force health protection issue.

This study provides a cross-sectional, population-based analysis of significant threshold shifts (STS) from over 83,000 audiograms on active duty members in the Navy Hearing Conservation Program Database for 1995-1999. Crude STS rates were lower for women than men (odds ration [OR], 0.82; 95% confidence interval [CI], 0.76-0.89; p = 0.0000) and lower for officer than enlisted (OR, 0.71; 95% CI, 0.66-0.76; p = 0.000000). STS rates also increased significantly with increasing age (chi2 for trend, 134; p = 0.0000). Compared with historical information, STS rates for officers were significantly lower (OR, 0.23; 95% CI, 0.18-0.27; p = 0.00000). Adjustment by logistic regression found STS rates were lower for women (OR, 0.837; 95% CI, 0.773-0.905; p = 0.000) and officer status (OR, 0.670; 95% CI, 0.619-0.725; p = 0.0000), and increased significantly with age. These findings warrant further investigation because they have programmatic implications on Navy hearing conservation and force health protection.

No abstract

This study presents audiometric information from 54,057 Navy enlisted personnel in the Navy and Marine Corps Hearing Conservation Program database from 1995 to 1999. The purpose was to compare current threshold shift patterns for Navy enlisted population with historical literature and review programmatic effectiveness issues. The data suggest that 82% of the population did not display significant threshold shift (STS) on the "annual" and "termination" audiograms, which increased to 94% after the "follow-up 2" examination. Compared with historical data, STS rates were significantly lower for the most junior enlisted personnel (EI-E3) (odds ratio = 0.34, P = 0.00, 95% confidence interval = 0.30-0.39) but not significantly different for more senior enlisted personnel (odds ratio = 0.96, P = 0.22,95% confidence interval = 0.90-1.03). STS rates did not appear to correlate with expected "high" and "low" noise exposure Navy enlisted occupations. This suggests further investigation to readdress the possible risk factors other than noise intensity/duration.