Occupational Noise Exposure and Its Physiological Effects on Auditory Function Among Factory Workers in Aba Industrial Zone, South East Nigeria

Background: Industrial noise pollution is a recognised occupational hazard with documented adverse effects on auditory physiology, including noise-induced hearing loss, tinnitus, and central auditory processing alterations. The Aba Industrial Zone in Abia State houses numerous manufacturing facilities where noise control measures are often inadequate. Professional documentation of auditory health outcomes in this workforce is urgently needed. Objectives: This study aims to assess the audiometric profile of factory workers in the Aba Industrial Zone, determine the prevalence of noise-induced hearing loss, and establish relationships between years of occupational noise exposure, ambient decibel levels, and audiometric thresholds. Methods: One hundred and twenty consenting factory workers will be recruited from three manufacturing plants. Audiometric pure tone threshold testing will be conducted at 500, 1000, 2000, 4000, and 8000 Hz. Ambient noise levels will be measured using a calibrated sound level meter. Occupational histories and personal protective equipment usage will be documented. ANOVA and regression analysis will identify exposure predictors of threshold shift. Expected Outcomes: Workers with more than ten years of exposure and without consistent hearing protection use are anticipated to demonstrate significant high-frequency sensorineural hearing loss consistent with noise-induced pathology. Conclusion: Findings will reinforce advocacy for enforceable occupational noise standards and audiometric surveillance in Nigerian industry. Keywords: noise-induced hearing loss, audiometry, occupational noise, factory workers, Aba.