OBJECTIVES: This study was conducted to assess changes in spirometric parameters after protective interventions among workers at a chlorine production plant in Semnan, Iran during 2012-2016. METHODS: This quasi-experimental study included 100 workers at a chlorine production plant in Semnan during 2012-2016. Spirometric parameters (forced vital capacity [FVC], forced expiratory volume in 1 second [FEV1], FEV1/FVC, peak expiratory flow [PEF], and PEF occurring in the middle 50% of the patient’s exhaled volume [PEF 25-75%]) were measured in all workers before the initial intervention in 2012. Protective interventions were then implemented for 4 consecutive years and the parameters were measured annually. A multivariable linear regression model was used to assess the factors affecting spirometric parameters before and after the protective interventions in SPSS version 24. RESULTS: The mean values of all spirometric parameters significantly increased after the protective interventions (p<0.05). Multivariable linear regression showed that age (β=-0.40), body mass index (BMI) (β=0.71; 95% confidence interval [CI], 0.11 to 1.31), and type of mask (β=-7.88; 95% CI, -15.96 to -0.46) had significant effects on the mean difference in FVC. Similarly, age (β=-0.35; 95% CI, -0.70 to -0.01), BMI (β=0.80; 95% CI, 0.20 to 1.41) and type of mask (β=-8.88; 95% CI, -16.98 to -0.79) had significant associations with the mean difference in FEV1. The type of mask (β=-12.81; 95% CI, -25.01 to -0.60) had a significant effect on the mean difference in PEF. CONCLUSIONS All spirometric parameters significantly increased in workers after protective interventions were implemented. Therefore, protective interventions to prevent respiratory disorders in workers exposed to chlorine gas are suggested.

OBJECTIVES: This study was conducted to assess changes in spirometric parameters after protective interventions among workers at a chlorine production plant in Semnan, Iran during 2012-2016. METHODS: This quasi-experimental study included 100 workers at a chlorine production plant in Semnan during 2012-2016. Spirometric parameters (forced vital capacity [FVC], forced expiratory volume in 1 second [FEV1], FEV1/FVC, peak expiratory flow [PEF], and PEF occurring in the middle 50% of the patient’s exhaled volume [PEF 25-75%]) were measured in all workers before the initial intervention in 2012. Protective interventions were then implemented for 4 consecutive years and the parameters were measured annually. A multivariable linear regression model was used to assess the factors affecting spirometric parameters before and after the protective interventions in SPSS version 24. RESULTS: The mean values of all spirometric parameters significantly increased after the protective interventions (p<0.05). Multivariable linear regression showed that age (β=-0.40), body mass index (BMI) (β=0.71; 95% confidence interval [CI], 0.11 to 1.31), and type of mask (β=-7.88; 95% CI, -15.96 to -0.46) had significant effects on the mean difference in FVC. Similarly, age (β=-0.35; 95% CI, -0.70 to -0.01), BMI (β=0.80; 95% CI, 0.20 to 1.41) and type of mask (β=-8.88; 95% CI, -16.98 to -0.79) had significant associations with the mean difference in FEV1. The type of mask (β=-12.81; 95% CI, -25.01 to -0.60) had a significant effect on the mean difference in PEF. CONCLUSIONS All spirometric parameters significantly increased in workers after protective interventions were implemented. Therefore, protective interventions to prevent respiratory disorders in workers exposed to chlorine gas are suggested.