Occupational Exposure to Inhalable Cotton Dust, Endotoxin and Health Problems Associated with Workers of Ethiopian Integrated Textile Industry
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Date
2021-07
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Addis Abeba University
Abstract
Background: Exposure to workplace hazards is a significant risk to workers' health in the textile
and garment. Objective measurement of personal inhalable dust and endotoxin level and the effects
of exposure to workers' health in this sector was not adequately investigated in Ethiopia.
Objectives: This study aimed to measure personal inhalable cotton dust and endotoxin
concentration, examine lung function capacity, and analyze registered diseases and injuries of
workers in the integrated textile factories of Ethiopia.
Methods and materials: Three independent studies were conducted to achieve the stated
objectives. Personal inhalable cotton dust and endotoxin level, cross-shift lung function status with
chronic respiratory symptoms and registered diseases and injuries are outcomes of the three
studies. The overall study objectives were crafted within the framework of the three levels of
occupational exposure: external exposure consider (inhalable dust and endotoxin), internal
exposure (cross-shift lung function) and effect (diseases and injuries). An institution-based crosssectional
and
comparative
cross-sectional
design
was
employed.
The
study
settings
were
at
three
industrial
zones
in two
regions
of the
country:
Amhara
Regional
State
and
Tigray
Regional
State.
The
study
involved
three
integrated
textile
factories
(Factory
1,
Factory
2
and
Factory
3)
and
two
soft
drinks
and water
bottling
factories
as
comparison
groups.
In the first study, ninety-six (96) repeated air samples were collected from sixty-four (64) workers’
breathing zone to analyze the personal inhalable cotton dust and endotoxin exposure levels. The
samples were collected from seven work sections or seven similar exposure groups (SEG) from
an integrated textile at Factory 1. The seven work sections are Carding, Open-end, Ring frame,
Preparatory, Fabric making, Batching and Sewing found in the four production departments
(spinning, waving, finishing and garment). Dust samplings were performed for a shift using a
conductive plastic inhalable conical sampler mounted with a 37mm glass-fibre filter. The pump
operated at a flow rate of 3.5 l. min
-1
. The Time Weighted Average cotton dust level was
determined by gravimetrical analysis and reported in mg.m
-3
. Endotoxin was extracted from the
cotton dust samples and analyzed using a quantitative kinetic chromogenic Limulus Amebocytes
Lysate test and reported as EU. m
In the second study, cross-shift lung function tests and chronic respiratory symptoms assessment
were performed among 306 workers from an integrated textile Factory 1 and 156 non-cotton
exposed workers. The lung function test was conducted before and after the work shift using a
portable spirometer (SPIRARE 3 sensor model SPS 320) for the parameters: Forced Expiratory
Volume in one second (FEV
1
) and Forced Vital Capacity (FVC). Moreover, the prevalence of
chronic respiratory symptoms was assessed through a face-to-face interview using a standardized
questionnaire adopted from the American Thoracic Society.
In the third study, a one-year registration of diseases and injuries of 7,992 workers were collected
from the three integrated textile factories (Factory 1, Factory 2 and Factory 3). Data were retrieved
from both the registration of factory clinics and human resources. Each worker has a chart/card in
the clinic, labelled with the name and unique worker's identification number, similar to the one
used in the human resource department database. All clinical consultations of workers during
March 2016 to February 2017 were extracted from the health archives of the factory’s clinic.
Exposure measurement, lung function and registered diseases data were entered into a Micro Soft
Office excel template, whereas the data of the respiratory symptoms were entered using
epidemiological information package (Epi-Info) version 7.1. All types of data were exported to
SPSS for analysis. Missing values, incomplete recording, outliers and inconsistent records were
checked and managed accordingly. The exposure assessment was described by the arithmetic
mean, standard deviation, geometric mean (GM), and geometric standard deviation (GSD). The
cross-shift change in FEV
1
(∆FEV
1
) and FVC (∆FVC) was calculated by subtracting the after-shift
value from the before-shift value. The Global Lung Initiative Quanjer GLI-2012 multi-ethnic
reference value for the African American ethnicity was used to estimate the predicted value and
the proportion of subjects with FEV
1
and FVC below the Lower Limit Normal (LLN). Prevalence,
percentage and proportion were used to describe the respiratory symptoms and the registered
disease conditions as categorical variables. The independent t-test was performed to analyze
exposure differences between work sections and to compare the cross-shift difference FEV
1
and
FVC among the textile and non-cotton exposed workers. A paired-samples t-test was performed
to compare the pre- and post-shift difference of lung function parameters. The correlation between
inhalable dust and endotoxin concentrations was analyzed using Pearson's correlation test.
Analysis of Variance (ANOVA) was also performed to compare the GM of personal inhalable dust, endotoxin exposure level, and endotoxin ratio to dust between departments and work
sections. The Pearson Chi-square test or Fisher's exact test, if the expected value was less than 5,
was used to testing the difference between the groups regarding the categorical variables. Logistic
regression analysis was used two times in the study by adjusting confounding variables: 1) to
compare the chronic respiratory symptoms between the integrated textile workers and control and
2) to identify work and personal factors associated with the registered work-related diseases and
injuries. Furthermore, the amount of reduced cross-shift lung function capacity among the
integrated textile workers was estimated using multiple linear regressions.
Results: In the external exposure measurement, the overall Geometric Mean (Geometric Standard
Deviation) of cotton dust and endotoxin level was 0.75 mg·m
−3
(2.6) and 831 EU· m
(5.4),
respectively. The highest dust and endotoxin concentrations were observed in the carding section
found in spinning department (1.34 mg· m
−3
) and (6,381 EU· m
−3
), respectively; while the lowest
cotton dust (0.46 mg· m
−3
) and endotoxin levels (76 EU· m
−3
) were found in the garment
department. There was a moderate linear relationship between personal inhalable dust and
endotoxin exposure (r = 0.45, p < 0.001). In the internal exposure assessment, the cross-shift lung
function reduction among textile workers (123 mL for FEV
1
and 129 mL for FVC) was
significantly higher than the control group (14 mL for FEV
1
and 12 mL for FVC) at p < 0.001.
The prevalence of chronic respiratory symptoms was significantly higher among textile workers
(54 %) than the controls (28 %). Breathlessness was the most prevalent chronic respiratory
symptom with the highest adjusted odds ratio of 9.4 (95 %; CI: 4.4–20.3). The prevalence of
respiratory diseases was highest (34 %), followed by musculoskeletal disorders (29 %),
gastrointestinal infection (21 %), peptic ulcer (19 %) and injury (17 %); the injury was the leading
cause of sick leave. About 69 %, 65 % and 60 % of textile, garment and support workers,
respectively, were diagnosed with a disease in one year. In the effect measurement, 27,320
consultations for different disease diagnoses were made by 5,276 (66 %) workers; claimed 16,993
workdays lost due to sick leave annually. Work-related and personal factors were associated with
diseases and injuries; textile department, females, older and workers with low educational status
had a significantly higher risk for most diseases than the support, male, young and workers with
higher educational level.
Conclusions: We found a high level of personal inhalable dust and endotoxin in external exposure
from workplaces. Eleven percent of the dust samples were higher than the Workplace Exposure
Limit set by the Health and Safety Executives (HSE) of the United Kingdom and 89 % higher than
the Dutch experts' recommendation for endotoxin exposure. A lower level of inhalable dust
exposure does not guarantee safe exposure to endotoxin in work sections. The textile workers had
a higher level of cross-shift lung function reduction in the internal exposure, which could be related
to external exposure. The prevalence of chronic respiratory symptoms was also higher among
textile factory workers compared to control. Majorities of the workers were diagnosed with
different types of diseases and injuries as an effect. The textile and garment production workers
had a higher risk of acquiring diseases than the support process workers, indicating that some
diseases might have resulted from the external exposure and development of internal exposure at
the workplace. Thus, factory clinics seem to be an essential source of evidence to understand the
burden of occupational diseases and injuries. Further, the study showed the link between exposure
and effect.
Recommendations: A comprehensive workplace hazard exposure assessment and worker's health
protection program in the integrated textile factories should be strengthened. The occupational
health and safety programs should be prioritized and focused on addressing the specific gaps and
needs of high-risk workers. Besides, factory management, occupational health and safety
practitioners, policy and regulatory bodies should be part of the program. Further research is
required to assess exposure measurement to other hazards, including cotton dust and endotoxin,
by tracking workers' exposure profiles to estimate cumulative exposure and relationship to disease
outcome. The occupational diseases and injuries study may be extended to compare the results
with the general population using a standard and similar diagnosis tool, the International
Classification of Diseases (ICD) code.
.
Description
Keywords
Integrated textile factory; cotton dust; endotoxin; cross-shift lung function; respiratory symptoms; diseases and injuries