Assessment of Respiratory Symptoms and Pulmonary Function Status among Workers of Flour Mills in Addis Ababa, Ethiopia: Comparative Cross-Sectional Study

Background. Flour dust in the respiratory tract affects lung function. Flour dust is a heterogeneous organic substance which can have a tendency to cause respiratory ailments. There is growing consensus on the deleterious effects of flour dust on respiratory symptoms and lung performance of flour mill workers. Methods. The study design was comparative cross-sectional. A total of 54 flour mill workers who work for more than eight-hour shift per day and 54 control subjects matched for sex, age, weight, height, and area of residence were enrolled. Anthropometric measurement was done. Lung function was measured by using a digital portable spirometer (Spiro Pro) based on the ATS guidelines. FVC, FEV1, FEV1/FVC, PEFR, and FEF25 %(-75) % were measured. Productive cough, dry cough, wheeze, and breathlessness were evaluated using BMRC questionnaire guidelines, administered through face-to-face interview. Result. This study showed statistically significant reduction in the mean values of pulmonary function tests in flour mill workers as compared to their matched controls. Reduction of pulmonary function indices in study subjects was significant for FVC (4.25 +/- 0.93 vs. 5.30 +/- 0.71, p<0.001), FEV1 (3.46 +/- 0.86 vs. 4.50 +/- 0.72, p<0.001), PEFR (5.43 +/- 2.43 vs. 7.87 +/- 2.53, p<0.001), and FEF25%-(75)%, (3.87 +/- 1.61 vs. 4.60 +/- 1.60, p<0.05), but not significant for FEV1/FVC (81.93 +/- 12.74 vs. 83.40 +/- 12.50, p>0.05). Flourmillworkers developed 27.7% of restrictive type and 11.1% of obstructive type of lung disorders. Percentage prevalence of respiratory symptoms was evaluated as dry cough (27.7% vs. 9.3%), productive cough (11.1% vs. 5.6%), wheeze (14.8% vs. 3.8%), and breathlessness (16.6% vs. 7.4%) in flour mill workers and controls, respectively. Conclusion. Based on the results of the present study, occupational exposure to flour dust could cause respiratory dysfunction, thereby reducing lung efficiency.