Respiratory symptoms and pulmonary function of traffic policemen in Thonburi

A cross-sectional study was conducted to assess whether traffic policemen working in Thonburi district of Bangkok had poorer respiratory health than the normal Thai population. The benefits of wearing masks as a preventative measure against the respiratory hazards of air pollution were assessed. Traffic policemen (n = 629) who had worked in Thonburi and male subjects (n = 303, the control group) were evaluated for respiratory symptoms using the British Medical Research Council questionnaire. Their pulmonary function was measured by spirometry. Only non-smokers were included in the final analysis and it was found that traffic policemen (n = 242) suffered significantly more cough or phlegm (18.6% vs 7.8%, P = 0.005) and more rhinitis symptoms (17.8% vs 7.8%, P = 0.009) than the control subjects (n = 129). The traffic policemen also had a significantly higher prevalence of abnormal air flow (FEV1 < 80% predicted) than the control group (21.1% vs 12.4%, P = 0.04). The mean values of FEV1 and FVC of the traffic policemen were significantly lower than the control group (3.29 +/- 0.5 L vs 3.43 +/- 0.5 L, P = 0.01 for FEV1 and 3.86 +/- 0.5 L vs 3.98 +/- 0.6 L, P = 0.047 for FVC). Traffic policemen who did not use protective masks had not only a significantly higher prevalence of abnormal FEV1 but also a significantly higher prevalence of abnormal FVC than the control group (35% vs 14%, P = 0.046). They also had higher relative risks of abnormal FEV1 (2.76 vs 1.63) and FVC (2.51 vs 1.23) than those who used protective masks. Multivariate analyses with controlling for age, height, and pack-years of cigarette smoking, revealed that the traffic policemen were significantly and independently associated with lower FEV1 and FVC. In conclusion, the traffic policemen who work in Thonburi have more cough and rhinitis symptoms and lower FEV1 and FVC than the normal Thai population. Traffic policemen who do not use protective masks have higher relative risks of abnormal FEV1 and FVC than those who use them.