Bronchial asthma among workers in Alexandria and its association with occupation, eosinophil count, total serum immunoglobulin E antibodies, and glutathione S-transferase genes polymorphism
AbstractIntroduction: Many workers in Alexandria are exposed to a variety of occupational and environmental allergens and/or irritants that predispose them to the development of bronchial asthma. The present study was conducted to determine the role of occupational exposure as a determinant of occurrence of bronchial asthma and to assess the possible role of total serumIgE; eosinophil count and GSTM1 and GSTT1 null polymorphism as risk factors for the development of bronchial asthma.
Methods: Acase control study was conducted in which 100 workers with bronchial asthma were compared to 100 non asthmatic controls regarding their occupational characteristics, bronchodilator responsiveness, blood analysis for eosinophil count, total serum IgE, GSTM1 and GSTT1 genotypes.
Results: Exposure to irritants and allergens were significantly higher among workers with bronchial asthma compared to controls (86% vs. 64%, respectively, P = 0.00). Moreover, workers exposed to irritants were found to be 4 times at a higher risk of developing bronchial asthma, and those exposed to high molecular weight (HMW), and/or low molecular weight (LMW) were about three times at a higher risk of developing bronchial asthma. There was no significant difference detected between the cases of bronchial asthma and the controls regarding the frequency of the Null-genotype for either GSTT1 or GSTM1. However, the frequency of combined Null-genotype for both GSTT1 and GSTM1 was significantly higher in asthmatic workers than in controls. A significant positive correlation was found between total serum IgE level and pre-bronchodilator FEV1/FVC% (r =0.29, and P =0.03).
Conclusion: Occupational exposure to irritants and/or allergens is a significant risk factor for the occurrence of bronchial asthma among workers. On the other hand, eosinophil count and total serum IgE neither predicts the occurrence of bronchial asthma nor affects the severity and pattern of the disease among workers with bronchial asthma. Moreover, the present study concluded that GSTM1 and GSTT1 Null-genotypes are not likely to act as risk factors for the development of bronchial asthma.
However, combined GSTT1andGSTM1Null-genotypes were considered as a potential risk factor for the development of bronchial asthma.