Pulmonary Function and Respiratory Symptoms in Railway Workers Exposed to Silica Dust in Southeastern Iran

Background : Railway maintenance workers are exposed to various pollutants, including silica dust, which can impair pulmonary function. This study aimed to quantify the impact of silica dust exposure on pulmonary function and respiratory symptoms among railway maintenance workers in southeastern Iran. Material and Methods : This case-control study was conducted on 63 sand-cleaning workers from the Zahedan-Fahraj railway line. Demographic variables including age, height, weight, body mass index, marital status, work history, smoking, and COVID-19 history USING demographic questionnaire. Blood pressure were measured using a Sphygmomanometer. Pulmonary function was assessed through spirometry, measuring FEV1, FVC, FEV1/FVC, PEF, and FEF25-75 parameters. All participants completed the American Thoracic Society Respiratory Symptom Questionnaire. Data were analyzed using SPSS version 26. Results : The exposed group showed significantly lower pulmonary function indices, including FEV1, FEV1/FVC, and PEF compared to the non-exposed group ( P < 0.05). However, no significant differences were found in FVC and FEF25-75 indices between the two groups ( P > 0.05). The mean of FEV1/FVC was significantly higher in the control than the exposed group even after adjusting for possible confounders ( P <0.001). Additionally, all respiratory symptoms including cough, phlegm, wheezing, and breathlessness were significantly higher in the exposed group compared the control group ( P < 0.001). Conclusion : Inhaling silica dust decreased pulmonary function and caused adverse respiratory symptoms in railway workers. This indicates a critical need for interventions to protect railway workers' respiratory health. These findings should inform local health policies aimed at reducing occupational exposures to dust in similar settings.