Abnormal Audiogram Risk Factors in Military Aircrew and Ground-Based Aviation Personnel

INTRODUCTION: The military aviation environment is inherently noisy, with occupational noise hazards from a variety of sources. At the same time, it demands good binaural auditory acuity and speech discrimination abilities for the safe and effective performance of flight duties. This study aimed to 1) examine the burden, characteristics, and severity of abnormal audiograms among military aircrew and ground-based aviation personnel in the Republic of Singapore Air Force; and 2) elicit the risk factors associated with abnormal audiograms.

METHODS: In this cross-sectional study, anonymized data (sociodemographic information, pure tone audiometry thresholds, anthropometric and physiological measurements, and biochemical investigations) were extracted from all consecutive unique annual certification examinations performed between January 1 and December 31, 2022. Multivariable logistic regression was performed to identify statistically significant risk factors associated with abnormal audiograms.

RESULTS: Of the 1817 audiograms, 83 (4.6%) were abnormal based on the modified World Health Organization criteria. Abnormal audiograms featured an early bilateral high-frequency hearing loss pattern characteristic of noise-induced effects. The multivariable model retained only age and four vocations [i.e., Communication Equipment Specialist, Air Force Engineer (Flight Engineer), Air Warfare Officer (Air Battle Manager), and Unmanned Aerial Vehicle Pilot] as significant risk factors. Neither aircraft platforms nor specific engine types were associated with higher odds of developing abnormal audiograms.

DISCUSSION: This study suggests that the modified World Health Organization criteria are useful in identifying at-risk subgroups within the military aircrew population and could be considered for use as a more sensitive screening threshold for early noise-induced hearing loss.

Seah BZQ, Ng WT, Gan WH, Low JW, See B. Abnormal audiogram risk factors in military aircrew and ground-based aviation personnel. Aerosp Med Hum Perform. 2025; 96(5):378–385.