Respiratory and other illnesses among the jute-mill workers in an industrial unit of Bangladesh

Background and aims: Bangladesh produces 33% of the world’s jute and about 40 million people in Bangladesh are directly or indirectly involved in the jute sector. The jute (organic) dust inhalation causes byssinosis and other respiratory illnesses. However, no study has yet addressed the health status of the jute handlers/workers in Bangladesh. This study aimed to determine the prevalence of respiratory illnesses among the Jute Mill Workers (JMWs). Additionally, this study tried to find out the overall health status of the JMWs which included presence of non-communicable diseases (NCD) and its related risk, which are usually ignored. Study design: A cross-sectional study conducted in a purposively selected jute mill 40km off from Dhaka City. Of the 5500 workers, a list of 600 workers was provided by the mill authority for enrollment in the study. The investigations included – a) interviewing on sociodemography and clinical history; b) anthropometry (height, weight, waistand hipcircumference); c) blood pressure measurement; d) estimation of fasting blood glucose and lipids; e) peak flow meter test; f) spirometry; g) high resolution computerized tomography (HRCT) and electrocardiography. Results: Of the enlisted 600 jute mill workers, 514 (men / women = 478 / 36) took part in the study. The response rate was 85%. For overall estimate of bio-physical characteristics (n = 514), the means (95% confidence interval) of age, body mass index (BMI), waist-hip ratio (WHR), systolic blood pressure (SBP) and diastolic blood pressure (DBP) were 44.19 (43.34 – 45.04) years, 24.44 (24.16 – 24.73), 0.90 (0.90 – 0.91), 118.9 (117.4 – 120.4), 79.69 (78.81 – 8/0.54), respectively. Regarding social class and education, 84.4% were from non-affluent (poor) class and 50% were illiterate. About 88% of the JMWs had been working for ≥42 hours a week and 91.6% were exposed to moderate or heavy work (equivalent to ≥60 min walk). The prevalence of breathlessness, tightness of chest and chronic cough were 16.5%, 25.7% and 16.3%, respectively. The restrictive and obstructive pulmonary functions were detected in 7.0% and 0.8% of study population respectively. The prevalence of systolic hypertension was 16.5%, diastolic hypertension was 7.2% and diabetes (IFG+DM) was 13.3%. They had increased cardiovascular risks – hypertriglyceridemia (23.9%) and hypercholesterolemia (24.3%). Conclusions: JMWs have been suffering mostly from respiratory illnesses and a substantial number of them suffer from undiagnosed hypertension, diabetes and other non-communicable diseases. Dyslipidemia was also prevalent as a potential risk factor. The study could not assess ocular, auditory, musculoskeletal and mental health and it suggests that a well designed study should address these health related problems of JMWs. IMC J Med Sci 2019; 13(1): 007. EPub date: 01 June 2019 Original Article Address for Correspondence: Prof. M. Abu Sayeed, Department of Community Medicine, Ibrahim Medical College, 122 Kazi Nazrul Islam Avenue, Shahbag, Dhaka-1000. email: sayeed@imc.ac.bd


Introduction
Byssinosis is a specific disease of respiratory organ caused mostly by an occupational exposure to organic dust from jute, cotton, hemp or flax [1]. These organic dusts are involved in pathogenesis of obstructing the small air tubes of the lungs. It may also cause permanent lung damage similar to chronic obstructive lung disease. It was reported that 22.8% workers in jute industry suffer from byssinosis-like illness [2]. In addition, the study showed acute and chronic changes of pulmonary function in 25.7% and 20.0% of workers respectively. Similar studies observed some acute and chronic changes of ventilatory function in 35.7% and 31.6% of workers, respectively [3,4]. Thus, it appears that about onefifth to one-fourth of the workers is at risk of byssinosis or similar pulmonary disorders.
Bangladesh is one of the largest jute producing country. More than 1.5 million workers are employed in 11,983 presently functioning looms of jute industries in Bangladesh [5]. It is estimated that 307 jute mills (government /non-government = 26 /281) have been producing jute goods. The jute products are exported to India, Syria, Tunisia, Turkey, Iraq, Thailand and other countries. The daily average wage of jute-mill workers (JMW) has been reported as BDT ~308.00 (approximately USD 3.6) [5]. The health status of the low paid JMW remained unknown. In Bangladesh, no study has been so far conducted to assess their health problems. The common occupational health problems of the JMWs as mentioned earlier [2,3], are byssinosis like illness with symptoms of cough, chest tightness and breathlessness and other respiratory diseases due to organic dust inhalation. The other non-communicable diseases (NCD) like diabetes, hypertension, coronary heart diseases, though prevalent among them, are usually ignored. Therefore, this study has been designed to determine the prevalence of the above mentioned disorders, and to detect hitherto ignored diseases and the risk factors related to those diseases.

Study design
This study protocol was approved by the Institutional Review Board of Ibrahim Medical College.

Selection of Jute mill and participants:
We purposively selected "Latif-Bawany Jute Mill". This mill has been functioning with full capacity for decades. It is situated at Demra about 45 km off Dhaka City by the side of a river, Shitalaksma.
The jute mill authority was contacted from Ibrahim Medical College. The investigators from the Medical College discussed regarding the objectives and procedural steps of the study in detail with the mill authority. Workers working in the mill for at least 5 years were enrolled in the study. Six hundred participants were selected from a total of 5500 JMWs. The selection was randomized from every morning shift so that the looms remain functioning without interruption. Verbal consent was taken from each participant. A semi-structured questionnaire was used for data collection. Each participant was interviewed regarding -i) personal history (age, education, social class, family income, employment, type and duration of dust exposure, smoking) and ii) clinical history (past and present illness, medication, family history of obstructive lung disease, diabetes, stroke, hypertension and coronary artery disease).
Anthropometry: Several anthropometric measurements namely height, weight, waist and hip circumference were taken to assess the general and central obesity status. Body mass index (BMI) was calculated using weight in kilogram divided by height in meter and expressed as kg/m 2 . Waist-to-hip ratio (WHR) and waist-to-height ratio (WHtR) were calculated as waist measurement divided by hip or height measurement respectively. BMI was used for determining the general obesity while the latter two (WHR, WHtR) indicated central obesity. Blood pressure of each participant was measured after ensuring at least ten minutes of rest in a complete relaxed environment. The means of two readings were accepted.  [6].

High resolution computer tomography scanning (HRCT) of lungs:
The participants having restrictive or obstructive lung diseases (based on spirometry) were referred to BIRDEM hospital for HRCT and recheck spirometry as well.

Electrocardiogram (ECG):
ECG was advised for those who had family history (first degree) of heart attack (sudden death), diabetes, hypertension and / or stroke. ECG was also done to those who were found hyperglycemic (FBG =>5.9 mmol/l), and hypertensive (SBP =>140 or DBP =>90mmHg).

Definitions of obstructive and restrictive lung function:
The best values of lower limit [LLN] and upper limit [ULN] of normal based on age, sex and ethnicity, using all loops, were obtained by Spirometry. If the predicted (%) values of forced vital capacity (FVC) and forced expiratory volume in one second (FEV1) were found within this limit then it was accepted as normal. Obstructive disease was diagnosed if FEV1/FVC was <70% and if the value exceeded 85% then it was diagnosed as restrictive lung disease [6][7][8].

Statistical analyses:
The biophysical characteristics were given in means with standard deviations. Unpaired student's t-test compared the characteristic variables between men and women. Chi-Sq estimated the associations between sex and diseases. Correlation coefficient 'r' assessed the associations between values of peak flow meter with that of spirometry.

Results
Of the enlisted 600 jute mill workers (JMW), 514 (men / women = 478 / 36) finally participated in the study. The response rate was 85%. The bio-physical characteristics of the total study population (n=514)   Table. Some anthropometric measures differed significantly. The peak flow value was found significantly higher in men than women. Socio-demographic variables of the participants are depicted in Table-2. The JMWs were predominantly men (92.9%). Regarding social class, 84.4% were from non-affluent (poor) and 50% were illiterate. About 88% of the JMWs have been working ≥42 hours a week and 91.6% were exposed to moderate or heavy work (equivalent to ≥60 min walk).
The interviewing session (clinical history and medical records) revealed that 14.6%JMWs had diagnosed diseases and 85.4% were (apparently) healthy (Table-3). These findings indicate that some non-communicable diseases (NCDs) were prevalent at any given time. The most common ailment, as revealed from history and medical records, was hypertension (HTN, 5.2%) and other common illnesses were diabetes mellitus (DM, 4.5%)) and HTN plus DM (3.5%). For respiratory illness, only two (0.4%) had bronchial asthma. Hypercholesterolemia was also significantly higher in men than in women (25.3% vs. 11.12%, p = 0.045). In contrast, restrictive pulmonary disorders were significantly more among women than that of men (30.6% vs. 5.23%, p = 0.004).
The prevalence of systolic hypertension was 16.5% and diastolic hypertension was 7.2% and there was no significant difference between men and women. Known hypertension was 5.3% (Table-3), if compared with Table-4 then it would be clear that many of them had undetected hypertension.
Likewise, diabetes also remained undetected (4.5% in Table-3, 11.9% in Table-4). As regards proteinuria the findings were similar ((0.2% vs. 3.1%). Only three participants (0.58%) had coronary heart disease. Interestingly, almost 1/4th of the study population had hypertriglyceridemia (23.9%) and hypercholesterolemia (24.3%). These findings indicate that these jute mill workers carry increased cardiovascular risks.     Notes as shown under Table-5; Peak flow -The means of three values (liter per min) were taken; FEF75% -amount of air expelled from the lungs in the first 75% of the total forced vital capacity; p value by student's t-test.
abnormalities. Table-6 compared the values between  normal and restrictive lung function and Table-7 showed the comparisons between normal and obstructive ones. Both the tables showed significant differences of spirometry values between normal and restrictive; and between normal and obstructive lung functions.
Descriptive statistics of spirometry values of a subsample of the JMWs are shown in Table- High Resolution Computerized Tomography (HRCT) was done in participants with restrictive and obstructive disorders. The HRCT findings were mostly helpful in diagnosing the restrictive cases, where fibrosis was evident. Mild to moderate obstruction could not be detected by HRCT though very severe obstruction was detected as evidenced by hyperinflation.

Discussions
This study is the first one that addressed the health of jute mill workers encompassing not only the respiratory illnesses but also other noncommunicable diseases. The prevalence rates of byssinosis like syndrome, observed in this study, are consistent with other study [2,3]. But the complaints of chest tightness symptoms observed in this study was much higher (25.7%) than found by Saha et.al (5.1%) [9]. However, Mandal and Majumder reported even much higher rate (33.49%) of chest tightness among jute mill workers from West Bengal, India [10]. A study from Benin, Africa reported the prevalence of chronic cough, breathlessness (dyspnea), asthma and chronic bronchitis as 16.8%, 17.3%, 2.6%, and 5.9% respectively among textile workers exposed to cotton dust [11]. The findings are almost similar to our observations. The prevalence of obstructive lung disease was much less (0.8%) than that of other studies (17% -28%) [12]. It may happen that the workers suffering from chronic obstructive pulmonary disease (COPD) are considered disable and removed from job. Thus, the prevalence of COPD among our study population was found low.
The term byssinosis has been used for long time to denote an obstructive airway disease due to inhalation of dust from cotton, flax, hemp, or jute, though it's diagnostic criteria are ill defined. Garson Hollander reported first (1953) a case of byssinosis [13]. Its diagnosis was based on "careful history" (chest tightness, breathlessness, chronic cough) and the chest x-ray showing pulmonary tuberculosis like appearance. No matter how carefully the histories are taken from such suspected cases, these symptoms are likely to vary and the diagnostic validity may be challenged. It may be suggested that the term byssinosis or the criteria for its diagnosis needs evaluation and should be based on objective scientific evidence and methods.
Most of the studies related to organic dust exposure, whether be it jute or cotton or silk, addressed only respiratory or ventilatory functional disorders. But, the illnesses of workers of these industries are not confined only to respiratory diseases. The other systemic illnesses need to be investigated. Our study not only addressed the respiratory diseases, but also focused into other systemic illnesses, which we considered important to assess the overall health of JMWs. The questions remained unanswered how healthy they are. It may be noteworthy to cite a report published online by Pyakurel et al from Nepal on "Catastrophic health expenditure among industrial workers" [14]. We emphasize that the industrial workers' health need comprehensive care (promotive, preventive, curative and rehabilitative), keeping in mind that they are indeed low paid marginalized section of the society. It is not known however, how many of the workers lose their jobs due to illnesses and disabilities.
This study had some important limitations. Many reports stressed that the exposure to both inhalable organic dust and airborne endotoxin are responsible for the pathogenesis of respiratory illnesses observed in cotton workers [15][16][17]. It may be mentioned that retting of jute is a special process where jute is soaked in a mixture of oil and water at 25 0 C for 48 hours. The bacteria that grow during the process help in softening and easy separation of individual fiber from the jute sticks. However, these bacteria also produce endotoxin. The workers handling this process are therefore, likely to be exposed to the bacterial endotoxin. This endotoxin has been reported to cause lung tissue damage [15]. In the present study, we could not measure the endotoxin level in work place of the JMWs where they were likely to get exposed to it.
As the jute mill workers are exposed to sound pollution, generated from looms, they are possibly at risk of developing hearing problem and mental irritability [18]. We could not assess these health problems. We also could not assess the ocular, auditory, dermal, musculoskeletal and mental illnesses. Had we performed the spirometry for all participants we could have more accurate rate of abnormal ventilatory functions of the JMWs. Physical activities were assessed using a crude estimation considering "x" min walking equivalent. It would have been better if we could assess their diet. Despite all those limitations this study explored some important information on health and diseases status of the JMWs.

Conclusions
This study concludes that a sizeable proportion of industrial workers, exposed to organic dust, have been suffering from respiratory illnesses. In addition, the study has revealed that a substantial number of this population suffers from undiagnosed hypertension, diabetes and other noncommunicable diseases. They also bear the brunt of undetected cardiovascular risk like dyslipidemia. It was not possible to determine the ocular, auditory, musculoskeletal and mental health problems. This study suggests that a well designed study should be undertaken addressing the limitations mentioned above.