Risk Factors for increased hearing threshold in workers exposed to continuous and intermittent noise in the heavy equipment industry in North Jakarta

Noise exposure can cause hearing disorders. Both intensity and type of noise contribute to hearing impairment. Different noise types can have different auditory effects. This study aimed to compare changes in hearing thresholds between workers exposed to continuous and intermittent noise. This study employed heavy equipment industry workers at the fabrication and assembly department. Data collected from questionnaires and medical records included age, marital status, cumulative time worked, blood sugar level, blood pressure, smoking habit, hobbies, and results of an audiometric examination. Of total 167 workers, 15 (9%) showed increase in hearing threshold. Of these 15, 13 (86.7%) and 2 (13.3%) had been exposed to continuous and intermittent noise, respectively. Workers aged over 40 years had more than fourfold risk of having an increased hearing threshold. Those who had worked for more than 3.9 years were at high risk of having an increased hearing threshold. Those who were exposed to continuous noise had nearly fivefold risk of having an increased hearing threshold as compared to those exposed to intermittent noise. Workers who are aged over 40 years, have worked in the industry for numerous years, or have been exposed to continuous noise are at increased risk for hearing loss.