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Assessment of the changes of spirometric parameters and factors associated in tiles and ceramic factory workers of Semnan city (Iran)

Introduction The present study aimed to evaluate the changes of spirometric parameters and factors associated in tiles and ceramic factory workers of Semnan city (Iran). Patients and methods This longitudinal study was conducted on 263 workers from the tile and ceramic factory of Semnan city (Iran) during 2012–2015. Two questionnaires were used for data collection. The first questionnaire consisted of demographic and occupational variables and the second questionnaire consisted of specifications of spirometric and chest radiograph tests, which were done for all workers in 2012 and 2015. Then, Wilcoxon and paired t test were used to evaluate the changes of spirometric parameters in the two time periods. To determine the effective factors on mean difference of spirometric parameters changes, univariate and multiple linear regression models were employed. In this study, data analysis was performed by STATA14. Results The means of forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1), and FVC/FEV1 parameters decreased significantly during the 3 years (P<0.05). However, this decrease was not significant for peak expiratory flow (PEF) and PEF (25–75%) (P>0.05). The results of multiple linear regression model demonstrated that sex [β=−10.23; 95% confidence interval (CI): −19.53 to −0.94], age (β=−0.19; 95% CI: −0.33 to −0.05), and duration of employment (β=−0.65; 95% CI: −1.88 to −0.12) have significant effects on mean changes of FEV1, FVC/FEV1, and PEF, respectively. Conclusion This study showed the most spirometric parameters were significantly reduced in tiles and ceramic factory workers during the 3 years. So, the fulfillment of regular periodic examinations and engineering preventive measures in this industry should be considered.