Prevalence and correlates of noise induced hearing loss among traffic policemen in the city of Colombo, Sri Lanka
Noise induced hearing loss (NIHL) is a high frequency sensory-neural hearing loss in subjects who are exposed to environmental noise when other reasons for the hearing loss are excluded. Traffic policemen are exposed to environmental noise due to nature of their duty and susceptible to develop NIHL.
The objective of this study was to determine the prevalence and correlates of NIHL among traffic policemen in the city of Colombo.
METHODS:
Study was a cross sectional descriptive 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 in 287 participants to assess the level of NIHL. The test was performed in a audiology laboratory and 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 an Interviewer Administered Questionnaire (IAQ).
RESULTS:
High frequency hearing of, 169 participants (169/287, 58.9%) were normal. Seventy nine participants (79/287, 27.5%) had minor NIHL and 39 participants (39/287, 13.6%) had major NIHL.
According to bi-variant analysis 23 variables showed statistically significant association with mild and major NIHL of traffic policeman in the city of Colombo. However according to multi-variant 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 in career” had statistically significant association with any NIHL (major or minor) with OR of 1.007.
CONCLUSIONS:
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.