key: cord-0252237-uaurgsnz authors: Malek, Farhad; Shomali, Amir; Mirmohammadkhani, Majid; Mansori, Kamyar; Pahlevan, Daryoush title: Effects of Chlorine Gas Exposure and Associated Factors on Spirometric Parameters in Detergent Industry Workers: a Four-Year Cross-Sectional Study date: 2021-01-03 journal: Tanaffos DOI: nan sha: 396c7ae93d643b6ae81cd2501a7b9ae2f1e3c4f8 doc_id: 252237 cord_uid: uaurgsnz BACKGROUND: This study aimed to determine the effects of chlorine gas exposure and the associated factors on spirometric parameters among detergent industry workers in Semnan, Iran. MATERIALS AND METHODS: This four-year cross-sectional study was concocted on 100 workers of two detergent factories in Semnan, Iran. Two questionnaires were used for data collection. The first questionnaire included demographic and occupational information, and the second questionnaire included spirometric parameters, such as forced vital capacity (FVC), forced expiratory volume in one second (FEV1), FEV1/FVC ratio, peak expiratory flow (PEF), and PEF 25–75%. The spirometric parameters were measured over four consecutive years by a trained technician. Next, to determine the effects of chlorine gas exposure and its associated factors on spirometric parameters, a generalized estimating equation (GEE) model was used. The correlation structure of GEE was considered to be autoregressive 1 (AR-1). Analyses were performed in STATA version 14. RESULTS: All spirometric parameters showed a decreasing trend during 2012–2015. The GEE model showed a significant association between chlorine gas exposure and all spirometric parameters; the beta-coefficients for the effect of exposure (year) on FVC, FEV1, FEV1/FVC ratio, PEF, and PEF 25–75% were −4.51, −6.46, −4.27, −6.09, and −10.29, respectively. Also, this model demonstrated a significant association between smoking and FEV1, PEF, and PEF 25–75%; the beta-coefficients for the effect of smoking on these parameters were −5.64, −8.88, and −5.75, respectively. Additionally, the GGE model showed a significant association between the body mass index (BMI) and FVC and FEV1 (P<0.05); the beta-coefficients for the effect of BMI on these two parameters were − 0.59 and −0.48, respectively. CONCLUSION: The spirometric parameters showed a decreasing trend over time among detergent industry workers; this decline was more remarkable among individuals with a history of smoking. Therefore, it seems necessary to implement screening programs and periodic active examinations for these workers. Occupational diseases, as defined by the World Health Organization (WHO), are diseases that are primarily contracted as a result of exposure to risk factors associated with work activities. Although these diseases have a lower incidence as compared to other debilitating disorders, studies show that a significant proportion of people are affected by these diseases, especially in industrial areas. The International Labor Organization (ILO) reported that about 2.78 million workers die annually due to workrelated disorders worldwide, which is more than twice the rate of road accident and war mortalities (1-3). Among work-related disorders, respiratory diseases are the most common occupational diseases with an increasing trend, accounting for 17% of all deaths from occupational diseases (1, 4). Among workers of various industries, workers exposed to gases and chemical vapors, particularly chlorine, are at a greater risk of respiratory diseases (4) (5) (6) . Toxicology of chlorine is almost entirely related to the effects of this substance on the respiratory system. Symptoms of chlorine poisoning are similar in humans and animals and range from simple respiratory irritations, spasms, bronchoconstriction, and bronchial or alveolar injuries to acute and chronic respiratory diseases (7, 8) . Although there is a high chance of recovery after termination of chlorine exposure and timely diagnosis and treatment, severe and prolonged exposure may lead to permanent and irreversible damages to pulmonary function (7, 9) . In humans, chlorine concentrations ≤10 ppm can enter the lower respiratory tract by breaking the defense system of the upper respiratory tract (10, 11) . Various studies have reported complications, such as shortness of breath, irregular breathing, irregular heartbeats, obstructive ventilatory impairment, reactive upper airway dysfunction syndrome (RADS), and decreased lung residual volume after exposure to chlorine (12) (13) (14) . Considering the abovementioned complications, screening tests are necessary for assessing the lung health of workers, especially those exposed to chlorine. Today, there are various screening tests for work-related pulmonary disorders. Among these tests, spirometry, due to high accuracy, easy access, and low cost, is the most appropriate test to measure the pulmonary function of workers in different industries (10, 15) . Conventional spirometry devices measure more than 20 different respiratory variables, the most valuable of which are forced vital capacity (FVC), forced expiratiory volume in one second (FEV1), and FVC/ FEV1 ratio (16) . Spirometry, if performed regularly among workers exposed to respiratory pollutants, can show pulmonary dysfunctions before the onset of clinical symptoms and abnormal findings on chest imaging (17) . Given the importance of workers' health in a country's industrial progress and production, besides limited studies on the effects of chlorine exposure on Iranian workers' pulmonary function, this longitudinal study aimed to investigate the effects of chlorine exposure and the associated factors on spirometric parameters among industrial workers in Semnan, Iran. In this four-year cross-sectional study, all workers of two factories in an industrial town were examined from July 2012 to July 2015. For the selection of factories, first, all factories with chlorine as the main material in the production process were determined (six factories), and then, two factories were randomly selected; both factories manufactured washing materials. The inclusion criteria were as follows: working in one of the factories during the study; having at least four years of work experience; having an acceptable respiratory function at the time of entering the study (2012); and being involved in the production process. On the other hand, the exclusion criteria were as follows: contraindications to spirometry (cardiac arrest and chest pain in the past six weeks, active bloody sputum, uncontrolled hypertension, and flu in the past three days); having a respiratory disease (asthma, rhinitis, bronchitis, and emphysema), a chest injury or surgery; working in other factories with exposure to other harmful materials; and addiction to any type of opium. Of 137 workers of the factories, 37 were excluded from the study, and a total of 100 subjects were finally examined. The pulmonary function was evaluated using a Based on the subject's height, age, and gender, the mean percentage of the predicted value for each spirometric index was calculated and reported. Before spirometry, essential instructions related to the test method and maneuvers were thoroughly given to the workers, and they were asked not to smoke or eat a heavy meal at least one hour before the test. For spirometry, the subjects were asked to stand for five minutes, and then, special clips were placed on their noses in a comfortable standing position. For each subject, three acceptable maneuvers were performed, and if a difference was observed in the FVC values (>5%), the test was repeated up to eight times to obtain the best volume, based on the predicted percentage for pulmonary function. In this study, the predicted percentage for pulmonary function was the measured capacity by spirometry, divided by the anticipated capacity (according to gender, age, height, and race) in spirometry and multiplied by 100. Besides, chlorine gas in the workstation was measured using gas sampling pumps and gas chromatography and then compared with the threshold limit value (TLV). Two questionnaires were used for data collection. The first questionnaire consisted of demographic and occupational information, including age, gender, body mass index (BMI), work history in the factory, smoking, medical history, and type of used mask, and the second one consisted of spirometric parameters, including FVC, FEV1, FEV1/FVC, PEF, and PEF 25-75%. Before data collection, the study objectives were explained to the workers, and then, informed consent was obtained from each participant. Also, this study was Other related information is presented in Table 3 . lower in the exposed group as compared to the unexposed group (18) . Also, in a longitudinal study by Gautrin et al., investigating changes in spirometric parameters and the associated factors in workers exposed to chlorine gas, the findings showed that the FVC, FEV1, FEV1/FVC ratio, PEF, and PEF 25-75% were significantly reduced over time (19) . In another study from South Carolina, USA, evaluating the pulmonary function before and after a large chlorine gas release, researchers observed a significant reduction in the mean FEV1 and FEV1/FVC ratio over time following exposure to chlorine gas (20) . Also, Medina-Ramón et al. showed that the incidence of lung lesions in female cleaning workers increased due to exposure to liquid chlorinated bleach (21 (20) . It seems that smoking and exposure to chlorine have a multiplicative interaction in pulmonary function and significantly increase or aggravate pulmonary lesions caused by chlorine gas (20) . Since smoking, even in small amounts, can cause different respiratory disorders in these workers, design and implementation of smoking cessation programs, especially in workers exposed to chlorine gas, seem essential. workers might have been exposed to chlorine gas and other chemicals affecting the spirometric parameters (e.g., outside the workplace), and it was not possible to control these environmental and occupational parameters; this issue was not considered in the results of this study. Therefore, design and implementation of occupational cohort studies with a larger sample size are recommended. In conclusion, the results of the present study showed that all spirometric parameters (FVC, FEV1, FVC/FEV1 ratio, PEF, and PEF 25-75%) decreased dramatically over a four-year period among detergent industry workers; this decline was more significant in workers with a history of smoking. Therefore, it seems necessary to implement engineering control measures to reduce the concentration of chlorine gas. Also, screening and periodic active examinations are essential before confirming the effects of chlorine gas on different industrial workers, especially detergent industry workers. Gastroenterology Organisation Global Guideline: Helicobacter pylori in developing countries Early implementation of WHO recommendations for the retention of health workers in remote and rural areas The effect of continuous care model on parents' knowledge and controlling symptoms and recurrence in children with nephrotic syndrome Historical review of the List of Occupational Diseases recommended by the International Labour organization (ILO) The characteristic state of health of ammonia nitrate producing workers Exposure to ammonia and acute respiratory effects in a urea fertilizer factory irritant agents in occupational domestic cleaning: a nested case-control study The long-term effects of occupational exposure to vinyl chloride monomer on microcirculation: a cross-sectional study 15 years after retirement Long-term outcome of biopsy-proven, frequently relapsing minimal-change nephrotic syndrome in children Molecular chlorine: health and environmental effects Persistent asthma syndrome after high level irritant exposures Long-term outcomes of acute irritant-induced asthma Which agents cause reactive airways dysfunction syndrome (RADS)? A systematic review Prediction of relapse by plasma lipoprotein(a) concentration in children with steroid-sensitive nephrotic syndrome Steroid-sensitive nephrotic syndrome: from childhood to adulthood Idiopathic nephrotic syndrome in Iranian children The Effect of Exposure to Low Levels of Chlorine Gas on the Pulmonary Function and Symptoms in a Chloralkali Unit Cross-sectional assessment of workers with repeated exposure to chlorine over a three year period Lung Function before and after a Large Chlorine Gas Release in Graniteville, South Carolina Short-term respiratory effects of cleaning exposures in female domestic cleaners Assessment of chlorine exposure in swimmers during training Transmission dynamics and control of severe acute respiratory syndrome Chlorine gas exposure and the lung: a review Association of Body Mass Index (BMI) with Lung Function Parameters in Non-asthmatics Identified by Spirometric Protocols Effect of Body Mass Index on respiratory parameters: A cross-sectional analytical Study We would like to express our sincere gratitude to the managers and detergent industries workers of Semnan city (Iran) for their cooperation in during the carry out of this research. The authors declare no conflicts of interest. The study was supported by Deputy of Research of Semnan University of Medical Sciences, Semnan, Iran.