Respiratory symptoms and illnesses among brick kiln workers: a cross sectional study from rural districts of Pakistan

Background: Occupational risk factors are one of the major causes of respiratory illnesses and symptoms, and account for 13% of chronic obstructive pulmonary disease and 11% of asthma worldwide. Majority of brick kilns in Pakistan use wood and coal for baking the bricks which makes the brick kiln workers susceptible to high exposure of air pollution. This study was designed to describe frequency of chronic respiratory symptoms and illnesses and study the association between these symptoms and different types of work. Methods: This was a questionnaire based cross sectional survey conducted among the brick kiln workers in Larkana and Dadu districts, Sindh, Pakistan. A total of 340 adult men were assessed using translated version of the American Thoracic Society Division of Lung Disease (ATS-DLD) questionnaire. Logistic regression analysis was done to determine the relationship between various socio-demographic and occupational factors (age, education, type of work, number of years at work, smoking status), and the respiratory symptoms and illnesses (chronic cough, chronic phlegm, wheeze, Chronic Bronchitis and asthma). Results: Results of the study show that 22.4% workers had chronic cough while 21.2% reported chronic phlegm. 13.8% had two or more attacks of shortness of breath with wheezing. 17.1% workers were suffering from Chronic Bronchitis while 8.2% reported physician diagnosed asthma. Amongst the non-smoking workers 8.9% had Chronic Bronchitis. Multivariate analysis found that workers involved in brick baking were more likely to have Chronic Bronchitis (OR=3.7, 95% CI 1.1-11.6, p=<0.05) and asthma (OR=3.9, 95% CI 1.01-15.5, p=<0.05) compared to those involved in carriage and placement work. Conclusion: A high frequency of respiratory symptoms and illnesses was observed among brick kiln workers. Age, nature of work and smoking were strong predictors of developing these symptoms and illnesses.