occupational tasks influencing lung function and respiratory symptoms among charcoal production workers a time series study

Accepted Manuscript Occupational Tasks Influencing Lung Function and Respiratory Symptoms among Charcoal- Production Workers: a Time-Series Study Walaiporn Pramchoo, Alan F Geater, Ph.D, Silom Jamulitrat, Sarayut L Geater, Boonsin Tangtrakulwanich PII: S2093-7911(16)30322-5 DOI: 10.1016/j.shaw.2016.11.006 Reference: SHAW 209 To appear in: Safety and Health at Work Received Date: March 2015 Revised Date: November 2016 Accepted Date: 20 November 2016 Please cite this article as: Pramchoo W, Geater AF, Jamulitrat S, Geater SL, Tangtrakulwanich B, Occupational Tasks Influencing Lung Function and Respiratory Symptoms among Charcoal- Production Workers: a Time-Series Study, Safety and Health at Work (2017), doi: 10.1016/j.shaw.2016.11.006 This is a PDF file of an unedited manuscript that has been accepted for publication As a service to our customers we are providing this early version of the manuscript The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain ACCEPTED MANUSCRIPT Occupational Tasks Influencing Lung Function and Respiratory Symptoms among Charcoal- RI PT Production Workers: a Time-Series Study Walaiporn PRAMCHOO, Epidemiology Unit, Faculty of Medicine, Prince of Songkla University Alan F GEATER, Epidemiology Unit, Faculty of Medicine, Prince of Songkla University SC Silom JAMULITRAT, Department of Community Medicine, Faculty of Medicine, Prince of Songkla University University M AN U Sarayut L GEATER, Department of Internal Medicine, Faculty of Medicine, Prince of Songkla Boonsin TANGTRAKULWANICH, Department of Orthopedic Surgery and Physical Medicine, Faculty Corresponding author: TE D of Medicine, Prince of Songkla University Alan F GEATER, Ph.D., Epidemiology Unit, Faculty of Medicine, Prince of Songkla University, Hatyai, EP Songkhla 90110, Thailand AC C Tel: 66-74-451165; Fax: 66-74-429754; email: alan.g@psu.ac.th Running title: Charcoal-production tasks and respiratory function ACCEPTED MANUSCRIPT Abstract Background: The tasks involved in traditional charcoal-production variously expose workers to charcoal RI PT dust and wood smoke This study aimed to identify specific tasks influencing lung function and respiratory symptoms Methods: Interviews, direct observation, and task/symptom checklists were used to collect data from 50 charcoal-production workers on non-work days followed by 11 workdays Peak expiratory flow rate (PEFR) was measured times/day Results: PEFR was reduced and the prevalence SC of respiratory symptoms increased over the first 6-7 workdays PEFR increased up to evening on nonwork days but not on work-days Loading the kiln and collecting charcoal from within the kiln markedly M AN U reduced the PEFR and increased the odds of respiratory symptoms Conclusion: Tasks involving entry into the kiln were strongly associated with short-term drop in PEFR and the occurrence of respiratory symptoms, suggesting a need for the use of protective equipment and/or the operation of an effective kiln Word count: 150 TE D ventilation system AC C EP Keywords: Charcoal-production worker; Peak expiratory flow rate; Respiratory symptoms; Wood smoke ACCEPTED MANUSCRIPT Introduction Charcoal is an important fuel in many countries A large amount of charcoal is consumed in developing countries, mostly in urban areas, such as Zambia, northeastern Brazil and Kenya In Kenya the charcoal industry employs over 700,000 people providing domestic energy for 82% of urban and 34% of rural households[1-3] Charcoal is a wood fuel made from burning wood in a low-oxygen environment [4,5] In the traditional setting charcoal production results in the emission into the ambient atmosphere of smoke and dust from the burning of wood and husk Wood smoke contains particulate matter and other toxic compounds such as carbon monoxide, carbon dioxide and nitrogen oxides [6,7] Humans exposed to wood smoke, whether in domestic setting or occupationally, have 10 been reported to have decreased lung function, and increased risk for respiratory symptoms, asthma 11 and chronic obstructive pulmonary disease [7-13] Thus, women who use wood as fuel for cooking 12 have more cough, dyspnea and asthma than women who use gas for cooking [14] Workers exposed 13 occupationally to smoke, such as firefighters, brick-kiln workers and charcoal-production workers, also 14 have been shown to have lower values of spirometry parameters and increased prevalence of 15 respiratory symptoms during and/or after exposure than before [8-10, 15,16] Charcoal workers were 16 found to have significantly more respiratory symptoms and poorer lung function parameters than 17 workers in non-exposed occupations in Crete [9] and in Thailand [10], and these effects were more 18 pronounced among charcoal workers who were smokers than those who were non-smokers [17] 19 In the traditional setting in Thailand a charcoal-production plant consists of a number of kilns which 20 are operated asynchronously and each worker may perform a number of different tasks, the major tasks 21 being carrying wood from the wood stack to place it beside the kiln, loading wood into the kiln, firing 22 the kiln to start the pyrolysis process and, after charcoal in the kiln has cooled down, collecting the 23 charcoal and putting it into sacks or baskets For any one worker, tasks performed may differ from day 24 to day and several different tasks may be performed on the same day Thus, the intensity of exposure 25 to smoke and dust may be quite varied Personal protective equipment is not used AC C EP TE D M AN U SC RI PT ACCEPTED MANUSCRIPT The aim of this study, therefore, was to identify the acute respiratory effects of the different tasks A 27 new analysis of time-series data (secondary data) previously collected to compare pulmonary function 28 and respiratory symptoms of charcoal workers and rubber tappers [10] was undertaken Identification 29 of the specific occupational tasks that most influence lung function in the short term, as reflected by a 30 reduction in peak respiratory flow rate (PEFR) and occurrence of respiratory symptoms, could be 31 useful for the rational planning and implementation of protective measures for these charcoal- 32 production workers RI PT 26 AC C EP TE D M AN U SC 33 ACCEPTED MANUSCRIPT Materials and methods 35 Fifty charcoal-production workers (28 males and 22 females) who were willing to join the study were 36 recruited from nine charcoal-production plants (3-7 workers per plant) in Ta Khun district, Surat Thani 37 province, southern Thailand Each charcoal plant included between and 20 separate kilns and the 38 cycles of kiln loading, kiln firing and charcoal collection were generally asynchronous among the 39 kilns All workers who had been employed in their current charcoal-production plant for at least year 40 were requested to join the study Subjects who had hypertension, hypotension, ischemic heart disease, 41 aneurysm in thorax or brain, cataract lasik eye surgery or respiratory infection or who were pregnant at 42 the time of the study were excluded The study was approved by the Ethics Committee of the Faculty 43 of Medicine, Prince of Songkla University An explanation of the study was given to all participants 44 and formal signed consent was obtained before any data were collected 45 Data collection included interviews using a questionnaire, direct observation, and measurement of 46 height, weight, blood pressure using an automatic blood pressure monitor, and PEFR using a portable 47 peak flow meter with a range of 60-900 dm3min-1 (Micro Peak; Kent, UK) A record form was used to 48 record data, covering PEFR, daily tasks undertaken, respiratory symptoms, and starting and stopping 49 times of working each day The questionnaire was adapted from the American Thoracic Society and 50 Division of Lung Diseases of the National Heart and Lung Institute questionnaire (ATS-DLD-78- 51 adult) [18] and pilot-tested with thirty subjects in a different district of Surat Thani province, and 52 revised before using it to collect data in this study In both the pilot and the actual study, the 53 questionnaire data were collected by the investigator, who face-to-face interviewed individual subjects 54 PEFR measurements were made on 14 consecutive days, the first days being non-work days and the 55 subsequent 11 days being workdays Each subject was measured four times in each day, namely in the 56 morning before starting work, at midday, in the evening after finishing work, and before going to bed 57 Three measurements were made and recorded in units of dm3/min at each time Measurements were 58 made by the researcher at morning, midday and after work but by the participant him/herself before AC C EP TE D M AN U SC RI PT 34 ACCEPTED MANUSCRIPT going to bed The tasks performed each day and any respiratory symptoms (cough, sputum production, 60 dyspnea, wheezing, nasal irritation, nasal congestion) that were experienced during the day were 61 recorded on a checklist after PEFR measurement after work by the researcher and before bed by the 62 participant On each day, each symptom was coded as if experienced and otherwise 63 Workers were instructed on how to make the PEFR measurements They were instructed to ensure the 64 PEFR meter was set to zero before making a measurement, to hold the meter by its handle, stand up 65 straight, inhale rapidly but not forcefully, insert the mouthpiece, seal the lips and exhale with 66 maximum force as soon as the lips had sealed around the mouthpiece The meter was then to be 67 removed from the mouth and the reading recorded The procedure was to be repeated twice Finally the 68 mouthpiece was to be removed and discarded and the meter wiped with alcohol 69 Statistical analysis 70 Descriptive statistics were used to summarize the general characteristics of the subjects The maximum 71 of the three PEFR readings at each measurement session was used for analysis [19] Mean daily PEFR 72 over the non-work days, over all 11 workdays and on each successive workday following the non- 73 work period were calculated Mean PEFR at each time of day was also calculated for non-work days 74 and according to tasks performed on workdays 75 Mixed-effects multiple linear regression modeling was used to estimate the independent effects of 76 worker characteristics, cumulative day of work following the non-work period, and the interaction of 77 time of day and tasks performed during the day on PEFR; and mixed-effects logistic regression 78 modeling was used to identify worker characteristics, cumulative day of work following the non-work 79 period and tasks influencing the occurrence of respiratory symptoms (cough, cough with phlegm, 80 phlegm, dyspnea, wheeze and sneeze) In these mixed-effect models, worker was considered to be the 81 random element and other variables to have fixed effects For each of the multiple regression models, 82 variables which showed some evidence of a relationship with outcome (P