Screening for Noise-Induced Hearing Loss among Palm Oil Mill Workers in Peninsular Malaysia: A Comparison across Noise Exposure Levels

Background: Palm oil mill workers in Malaysia are exposed to hazardous levels of noise in the workplace, and thus are at risk of developing noise-induced hearing loss (NIHL). In 2019, Malaysia introduced a new noise regulation, which reduced the level of permissible noise exposure. Objectives: This study aims to determine the prevalence of NIHL among palm oil mill workers based on screening data and assess the effects of different noise exposure levels on NIHL. Methods: A cross-sectional study was conducted by analyzing data from noise risk assessment reports of selected mills and screening audiometric data from workers. NIHL was defined as bilateral high-frequency hearing loss. Results: The overall NIHL prevalence was 50.8%. Noise exposure level and age were significant predictors of NIHL among the workers. The risk of developing NIHL was high even for workers who were not categorized in the high-risk group. Conclusions: In view of the findings, a precautionary approach is needed when evaluating the risk of NIHL in the study population. Vulnerable groups of workers must be protected from occupational noise hazards through the implementation of effective hearing conservation programs in the workplace.