Noise-induced hearing injuries among military working dog handlers, 2012–2023

Objective: This study examines noise-induced hearing injuries, among active component service members in Military Working Dog (MWD) handler occupations compared to active component veterinary personnel, military police, and all other active component service members between 2012 and 2023. Methods: A total of 3,373,990 active component service members were included, with 5,112 service members in the MWD handler occupation. 2,726 veterinary personnel, and 157,811 service members working as military police. Crude incidence rates and adjusted incidence rate ratios were calculated for any noise-induced hearing injury, as well as for significant threshold shifts, sensorineural hearing loss, noise-induced hearing loss, and tinnitus. Results: During the surveillance period, MWD handlers sustained the highest incidence rate of noise-induced hearing injuries (416.84 cases per 10,000 person-years) compared to veterinary personnel, military police, and other military occupations. Incidence rates of tinnitus were higher than other noise injury types for all occupations and were highest among MWD handlers (262.51 cases per 10,000 person-years). During the surveillance period, incidence rates of tinnitus among MWD handlers steadily increased from 2016 (150.37 cases per 10,000 person-years) until it peaked in 2023 (607.80 cases per 10,000 person-years). Regardless of occupation, the incident rate ratio of any hearing injury increased with increasing age and was highest among MWD handlers who were 45 years and older [IRR = 5.63 (95%CI: 2.89–10.98)]. Conclusions: This study is among the first investigations into MWD handlers’ noise-induced hearing injuries.