Prevalence and correlates of noise induced hearing loss among traffic policemen in the city of Colombo

Abstract

INTRODUCTION: Noise induced hearing loss (NIHL) is a high frequency sensory-neural hearing loss in subjects who are exposed to environmental noise, but this diagnosis is made only after excluding other reasons for the hearing. Traffic policemen are exposed to environmental noise due to the nature of their duty and are susceptible to develop NIHL. OBJECTIVE: The objective of this study was to determine the prevalence and correlates of NIHL among traffic policemen in the city of Colombo. METHODS: This was a cross sectional study and traffic policemen working in the city of Colombo were selected for study. Cluster sampling method was adopted to select 350 participants. Pure tone audiometry test was performed to assess the level of NIHL. The test was performed in an audiology laboratory or in a sound treated, air-conditioned conference hall. Hearing levels of participants were classified according to a classification obtained by modifying the Clark’s classification. Correlates of NIHL were assessed using information collected using an Interviewer Administered Questionnaire (IAQ). RESULTS: Pure tone audiometry was performed on 287 policemen. High frequency hearing of, 169 participants (58.9%) was normal. Seventy nine participants (27.5%) had minor NIHL and 39 participants (13.6%) had major NIHL. In bivariate analysis 23 variables showed statistically significant association with mild and major NIHL of traffic policeman in the city of Colombo. However according to multi-variate analysis only age had statistically significant association with major NIHL with odds-ratio (OR) of 1.088 while only “duration of work as a policeman” had statistically significant association with any NIHL (major or minor) with OR of 1.007. CONCLUSIONS AND RECOMMENDATIONS: Prevalence of NIHL among traffic policemen working in the city of Colombo was 41.1% (95% CI=35.5%–46.9%). A third of those having NIHL had major NIHL. Traffic policemen should undergo periodic hearing assessment. The police department should explore the feasibility of reducing the number of hours per day spent on the road by traffic policemen. Traffic policemen with NIHL must be transferred to a different division immediately.