Audiological Profile of Heavy Vehicle Drivers: A Cross-sectional Study from Southern India

Introduction: Noise-Induced Hearing Loss (NIHL), a permanent sensorineural hearing loss that usually develops undetected until it becomes functionally significant, can result from ongoing exposure over time. Aim: To ascertain the prevalence of hearing loss and the audiological profile among heavy vehicle drivers in South India. Materials and Methods: A cross-sectional study was conducted at the Department of ENT, Chettinad Hospital and Research Institute (a tertiary care centre), Chettinad Academy of Research and Education, Kelambakkam, Chennai, Tamil Nadu, India, from September 2024 to February 2025 among 90 participants. The study population consisted of heavy vehicle drivers (e.g., truck, bus, or lorry drivers) aged 18 to 60 years with a minimum of five years of occupational exposure, attending the Ear, Nose and Throat (ENT) Outpatient Department (OPD). Demographic details, local examinations and pure tone audiometry were conducted for all eligible participants and the findings were documented. A paired t-test was applied to find the difference in hearing loss between the left and right ears. A p-value of <0.05 was considered statistically significant. Results: The overall percentage of hearing loss among the 90 drivers was 26 (28.9%) in their better ear (right ear) and 30 (33.3%) in their left ear. However, at higher frequencies (3000 Hz to 8000 Hz), the mean hearing loss was consistently greater in the left ear compared to the right ear. The differences were statistically significant at 3000 Hz, left ear (30.5 dB) vs. right ear (28.9 dB) (p=0.041); at 4000 Hz, left ear (37.8 dB) vs. right ear (35.2 dB) (p=0.028); at 6000 Hz, left ear (45.1 dB) vs. right ear (42.7 dB) (p=0.015); and at 8000 Hz, left ear (43.9 dB) vs. right ear (40.6 dB) (p=0.008). Conclusion: There is a significant increase in hearing loss in the left ear compared to the right ear at higher frequencies (≥3000 Hz), indicating that high-frequency hearing may be more affected in the left ear among the study population.