Respiratory Symptoms and Factors Influencing Respiratory Health among Bus Drivers and Conductors in Selected Depots of Sri Lanka Transport Board, Colombo District

Abstract

Background: Traffic-related air pollution (TRAP) significantly impacts human respiratory health. Bus drivers and conductors are among the groups that are highly exposed to TRAP daily. Objective: To assess respiratory symptoms and factors affecting the respiratory health of bus drivers and conductors in selected depots of Sri Lanka Transport Board in Colombo District Methods: A cross-sectional study was conducted among a total of 262 bus drivers and conductors from Avissawella, Homagama, Kesbewa, and Maharagama depots. Respiratory symptoms were assessed using the British Medical Research Council’s (BMRC) questionnaire on respiratory symptoms. Each participant was given a respiratory symptom score using the BMRC questionnaire, with higher scores indicating higher morbidity. Work-related factors; i.e. years of experience, shift duration, travel distance, work schedules, and resting time were collected using a pre-tested interviewer-administered questionnaire. SPSS version 25.0 was used to analyse data, and p<0.05 was considered statistically significant. Results: The mean±SD age of the sample was 46.2±7.4 years. According to BMRC questionnarie, phlegm (64%, n=168) was identified as the most common respiratory symptom, followed by breathlessness (51%, n=134). A total of 88% (n=230) reported having at least one symptom, and 60% (n=157) reported having severe, persistent respiratory symptoms. Respiratory symptom scores increased significantly with increased years of experience (r=0.75), longer shifts (r=0.93), and less rest (r=-0.49) (p<0.05). Participants on day duty shifts had higher BMRC respiratory symptom scores than those on night shifts (5.02±3.2 vs. 4.01±3.0, p<0.05). Long-distance travellers showed significantly higher BMRC respiratory symptom scores than short-distance travellers (7.62±3.0 vs. 3.22±2.1, p<0.05). Conclusions: Bus drivers and conductors showed more respiratory symptoms, stressing the need for regular screening and better work conditions. Limitations include considering air pollution and other confounders, limited generalizability, non-specificity and self-report bias of BMRC questionnaire.