Associations of sputum eosinophilia with pulmonary function and respiratory symptoms in bakery workers

Occupational flour inhalation has been a culprit in commence of several pulmonary maladies, such as asthma. The flour particle is one of the most important factors which can cause occupational chronic respiratory disorders. We examined the relationship of occupational wheat flour inhalation in bakery and supermarket employees with pulmonary function, respiratory symptoms, and sputum eosinophilia for determining hyper-responsiveness. 110 subjects from traditional bakeries and 137 subjects from supermarket employees were enrolled in a cross-sectional study in Iran. Flour exposure concentrations, respiratory signs, sputum analysis, and respiratory volumes and capacities were measured based on the standard methods. Independent sample t-test was applied for analyses. Respirable concentration of flour in the bakery workers was two to four-fold of ACGIH’s threshold limit value in which bread-bakers with 2.2 mg/m3 experienced maximum exposures among all job titles in the bakeries. The supermarket employees had not exposure to flour dust. The respiratory volumes in both bakery and supermarket employees were in the normal range. However, the median of voluminal percentage in bakery workers except forced vital capacity was reduced (p < 0.001). The mean respiratory volume of bread-bakers was reduced compared with supermarket employees (p < 0.05). In addition, we observed increased respiratory symptoms in the bakery workers, again more prevalent in the bread-bakers. There was a significant correlation between flour exposure concentration and sputum eosinophilia in which the percentage of eosinophilia in the bread-bakers was more than other bakery and supermarket employees. Albeit there were reductions in the respiratory volumes, results indicate no obstructive spirometric pattern. Noteworthy, sputum eosinophilia might be a suitable screening method to detect airway hyper-responsiveness in workers exposed to known asthmogens.