Epidemiology of hearing impairment and noise-induced hearing injury among U.S. military personnel, 2003-2005

Abstract

Introduction: Rates of noise-induced hearing injury (NIHI) among U.S. active duty military have not been previously described using available military medical surveillance data.

Methods: NIHI were identified in the Defense Medical Surveillance System (DMSS) using a list of ICD-9-CM diagnosis codes selected in collaboration with military audiologists. To provide a more comprehensive view of the NIHI problem, NIHI-related ICD-9 codes beyond the traditional 388 noise injury-code set were included. Visit rates by gender and age group are reported by quarter, 2003-2005. Overall frequencies and rates by occupational specialty, 2003-2005, are also described.

Results: From 2003 to 2005, rates for men were significantly higher than rates for women, with rate ratios (RR) ranging from 1.15 (95% CI =1.07, 1.23) to 1.78 (95% CI= 1.62, 1.93). Rates among women ranged from 2.9 to 6.2 per 1000 person-years; rates among men ranged from 4.5 to 6.7 per 1000 person-years. NIHI rates were highest among those aged > or =40 years and lowest among those aged 17-19 years, with RRs ranging from 3.06 (95% CI=2.77, 3.40) to 5.51 (95% CI=4.88, 6.30) during this time period. Among occupational groups, general officers/executives had the highest NIHI rate over this time period (29.5/1000 person-years), followed by enlisted personnel in training (14.3/1000 person-years) and scientists and professionals (12.8/1000 person-years).

Conclusions: While data on outpatient injury causes and use of hearing protection are also needed to guide the future design and/or modification of interventions, existing military medical surveillance provides essential information for tracking NIHI and monitoring NIHI intervention effects.