Are serum eosinophilic cationic protein levels of toll collectors affected by diesel exhaust exposure?

OBJECTIVE There are few studies on the diesel exhaust particulates (DEP) / eosinophilic cationic protein (ECP) level relationship. This study aimed to detect ECP levels in a highly DE exposed group, named as toll collectors. METHODS In a cross-sectional study, levels of serum ECP, rates of respiratory symptoms, mean levels of respiratory functions, smoking status, and variations in peak expiratory flow (PEF) during weekends and working days were compared for 68 toll collectors (TC) (range of age, 24-48 years) and 28 controls (range of age, 25-61 years). All subjects in the study group were men. RESULTS No significant difference was observed in terms of symptoms and smoking rates between the toll collectors and control group. The number of toll collectors [12/68 (17.7%) vs 1/28 (3.5%)] with diurnal PEF variability in the working period was higher than that of controls (p=0.058). Mean ECP level of toll collectors was higher than that of controls (32.8 vs 21.4 ng/L), but the difference was not significant. Mean ECP levels were higher in subjects experiencing diurnal PEF variability during work and off-work periods (34.9 vs 28.3 ng/L, p=0.410). CONCLUSIONS Serial PEF measurements combined with serum ECP measurements did not add a new tool to detect the sensitivity of workers dealing with DE. Much more diesel exhaust exposed workers should be included to search for cheap and available methods when evaluating airway.