Assessment of work
postures and prevalence of musculoskeletal disorders among porcelain industry
workers
Ahmadi
A, MSc1, Mirzaei R, PhD2*, Ansari H, PhD3
1-MSc student, Dept.
of Environment
Management (HSE), Faculty of Engineering and Technology, Islamic Azad
University, Zahedan Branch, Zahedan,
Iran. 2-Professor, Dept. of Environmental and Occupational Health
Engineering, School of Health, Mashhad University of Medical sciences,
Mashhad, Iran. 3- Assistant prof., Health Promotion
Research Center, Zahedan University of Medical
Sciences, Zahedan, Iran.
Abstract Received:
March 2016,
Accepted: May 2016
|
Introduction: Today, the prevention of
work-related musculoskeletal disorders (MSDs) is considered as a vital issue
and one of the highest national priorities. This study was conducted with the
aim of evaluating occupational postures and the prevalence of MSDs among porcelain
industry workers of the city of Rasht, Iran. Materials
and Methods:
This cross-sectional study was done in 2015 on 66 workers, active in
different factory units and chosen through stratified random sampling. To
determine the frequency of MSDs symptoms in different body parts of the
workers, the Nordic Musculoskeletal
Questionnaire (NMQ) and Job Content Questionnaire (JCQ) were used. To
evaluate the risk of MSDs, the Rapid Entire Body Assessment (REBA) method was
utilized. Descriptive statistics, chi-square test, independent t-test, and
logistic regression were used for data analysis. Results: Based on the data obtained
through the questionnaires, 36% of the studied population had experienced
pain at least in one body part in the last 12 months. The frequency of pain
in the waist, hand and wrists, and neck was the most. According to the data
collected through JCQ, the total score of job content had a statistically
significant relationship with subjects’ age and their occupational background
(P < 0.001, r = -0.549, and r = -0.704, respectively). Mean REBA scores of
workers suggested that printing, carpentry, engineering, and material
supplement units (scores: 6-6.5) were the most dangerous units, and the
enameling unit (score: 4) had the least amount of risk in the porcelain
industry. Conclusions: The present study indicated
that, in the studied industry, work posture correction with the help of
correction stations and appropriate training is absolutely necessary. |
Keywords: Assessment, Musculoskeletal, Disorders,
Porcelain, Industry, Questionnaire, Job
Introduction
Musculoskeletal
disorders (MSDs) are the major causes for workers’ inability, expense raise,
and efficiency reduction in industrialized and developed countries. Contrary to
many work-related diseases, whose source is contact with a certain dangerous
substance/material, MSDs are multifactorial and have
various psychological, social, and individual causes in addition to physical
causes.
Force,
posture, recurrent and repetitive movements, and work duration are important
physical risk factors in the emergence of MSDs. In 2010, Shaou et al. performed a study on
MSDs among construction workers in the western states of Bengal, India, using
Rapid Entire Body Assessment (REBA) and the Nordic Musculoskeletal
Questionnaire (NMQ) (1). They found* that the
practical stages of REBA were stage 3 and stage 4, and the frequency of pain
was high in different body parts of the workers, such as the waist. They also
reported that by training workers on the correct form of load lifting,
predicting break time, correcting work methods, and designing ergonomic
facilities, MSDs among construction workers would be prevented (1).
Maulik and Iqbal
conducted a research on MSDs among medical laboratory technicians of a
university in India using the NMQ and Quick Exposure Check (QEC) method (2).
Their results showed that 66.9% of technicians had been suffering from MSDs for
12 months and the frequency of pain in the waist (44.0%), knees (20.7%), and
neck (18.4%) was the highest in these subjects. They concluded that there was a
high or very high risk of MSDs among 85.3% of laboratory technicians. Moreover,
this study showed a statistically significant relationship between the risk
level and the prevalence of MSDs among technicians (P < 0.05), and most of
the observed risk factors were inappropriate standing postures and work
stations (2).
Maulik et al. also conducted a study on
work postures and prevalence of MSD symptoms among medical technicians using
the NMQ and Rapid Upper Limb Assessment (RULA) (3). Their findings indicated
that MSDs were more common among 73.3% of technicians, and pain locations were
mostly the trunk, knees, neck, and ankles. Additionally, the statistical
results demonstrated that there was a significant relationship between the MSD
scores before and after work (3).
Moreover,
in 2004, in a study by Punnett et al., checkups on 8200 workers showed that the
observed symptoms in distal MSDs had a relationship with stressful ergonomic
factors and job content. They were also related to the gained scores (4).
Considering
the literature, posture analysis is an efficient way of evaluating work
activities, and posture or body position as a source of MSDs has attracted
attention. Posture analysis is a suitable method for evaluating activities
which are done while standing and are performed with pressured upper or lower
body parts.
This
study was conducted with the objective to determine work postures and
prevalence of MSDs among porcelain industry workers. It is hoped that, with the
help of this study, the attention of the related authorities is drawn to the
side effects and hazards of MSDs and the evaluation of ergonomic risk factors
of occupations in the porcelain industry. It is also hoped that this will
result in the implementation of the required measures to provide the standards
of a work environment, execution of safety and health regulations, maintenance
of workers’ health, increased production and product quality, and society’s
economic growth.
Material and Methods
The participants of this cross-sectional
study were selected through stratified random sampling from among porcelain
industry workers of the city of Rasht, Iran, in 2015. The participants were
divided into two groups of subjects with and without pain. Some demographic
variables of the workers, such as age and education level, and discomfort were
studied. Sample size was calculated based on the sample size formula with
α equal to 10%, approximate prevalence of 75%, and accuracy of 5%. The
height and weight of the subjects were measured using a tape meter (accuracy
mm) and scales (accuracy 100 mg), respectively, and body mass indexes (
The data related to the prevalence
of MSDs in the 49 weeks was collected using the NMQ and Job Content
Questionnaire (JCQ) based on psychological and psychological-occupational
requirements. Using a questionnaire containing 20 items, physical and mental
occupational requirements can be evaluated in terms of workers; and the impact
of mental and subjective factors on the prevalence of MSDs can be examined. The validity of the questionnaire was approved
with at least 0.83 content validity index (CVI) for every question by 8 experts. The reliability of the NMQ and
JCQ was approved using Cronbach's alpha (α = 0.72 and
0.62, respectively). Workers
who had a congenital / inborn disorder or had undergone surgery due to
non-occupational disorders were not considered into account.
Figure 1:
Rapid Entire Body Assessment (REBA) score sheet
REBA was utilized to evaluate work postures
(inappropriate position of body parts while working), which enables us to
analyze the position of body parts during work and evaluates the ergonomic
condition of the occupation. In REBA, different work stages were filmed in
order to identify the postures. Next, the studied postures were chosen to
include at least one or several samples of each class, ergonomically highly
risky or very damaging to the musculoskeletal system. Then, each of the 9
joints in the chosen postures was closely examined. After encoding the data
using SPSS software (version 20, SPSS Inc., Chicago, IL, USA), they were
analyzed using Spearman correlation test. For data description, descriptive
statistics, including central and dispersion indexes and statistical charts and
graphs, were used. For data analysis, in order to determine the relationship
among all qualitative variables, chi-square test, and to determine the
relationship between qualitative and quantitative variables, independent t-test
or ANOVA were used. Multiple logistic regression
was used to investigate the effect of predictive factors on pain among workers
by controlling potential confounders. All P
values of less than 0.05 were considered significant.
Table
1: Rapid
Entire Body Assessment (REBA) decision
|
REBA score |
Risk level |
Action level |
|
2-3 |
Low |
Corrective action including further
assessment may be necessary |
|
4-7 |
Average |
Corrective action including further
assessment is necessary |
|
8-10 |
High |
Corrective action including further
assessment is necessary soon |
|
11-15 |
Very high |
Corrective action including further
assessment is necessary now |
Results
In
this study, 66 male workers with a mean age of 35.7 ± 7.1 years, weight of 82.6
± 12.4 Kg, height of 172 ± 14.2 cm, BMI of 28.2 ± 6, and job experience of 11.2
± 6.6 years were studied. As illustrated in table 2, the most frequent pain and
disorder location in the last 12 months among the workers was the waist. In
this study, 17 workers (25.8%) had no problem in any body parts. Moreover, 40
workers (60.6%) had diploma, and 18 of them (27.3%) had an education degree
less than diploma and 8 of them (12.1%) were higher than diploma.
Based
on the results of data analysis and chi-square test, there was no statistically
significant relationship between hand dominance (left-handedness,
right-handedness) and pain, discomfort, and numbness in the last 12 months (P =
0.492). A statistically significant difference was observed between the average
job backgrounds of the two groups of “with pain” and “without pain” (P <
0.001); the longer is the work experience, the greater is the pain. There were
no significant differences between the average BMI of the two aforementioned
groups (P = 0.071). Furthermore, Fisher’s exact test displayed a significant
difference between the education levels of these two groups in the last 12
months (P = 0.004). Thus, it is concluded that, more educated people had less
pain and MSDs.
Table 2:
Pain, discomfort, and numbness distribution during the last 12 months based on
the studied organ
|
Frequency |
The 9 body parts |
|
|
Percentage |
Number |
|
|
51.5 |
34 |
Neck |
|
47.0 |
31 |
Shoulders |
|
42.4 |
28 |
Elbows |
|
53.0 |
35 |
Hands and wrists |
|
13.6 |
9 |
Back |
|
57.6 |
38 |
Waist |
|
1.5 |
1 |
Buttocks and thighs |
|
34.8 |
23 |
Knees |
|
22.7 |
15 |
Legs and ankles |
In
reviewing distribution indexes of job content condition, as indicated in table
2 and figure 1, there was a significant and reverse relationship between total
JCQ score and the subjects’ ages (P < 0.001 and r = - 0.549). Furthermore,
there was a statistically significant relationship between total JCQ score and
the occupational background of the participants (P < 0.001 and r = - 0.704).
However, the results of ANOVA showed no significant difference between average
scores of physical occupational requirements (P = 0.096), psychological
occupational requirements (P = 0.161), and job content operation (P = 0.120) at
various educational levels (Figure 2).
Figure 2: Categorization
of the studied workers based on job content scores
As
observed in table 3, the majority of the workers obtained an average or high
REBA score, and 86.4% of them needed to practice corrective measures. There was
no statistically significant relationship between REBA score and BMI, age, and
job experience of the workers, and the observed correlation was not noticeable
(P > 0.05).
Table 3:
Risk level distribution among porcelain industry workers based on Rapid Entire
Body Assessment (REBA)
|
Percentage |
Number |
REBA score |
Risk level |
|
13.6 |
9 |
2-3 |
Low |
|
63.6 |
42 |
4-7 |
Average |
|
21.2 |
14 |
8-10 |
High |
|
1.5 |
1 |
11-15 |
Very high |
As
shown in table 4, based on the results of logistic regression job background,
education, and BMI had no statistically significant relationship with pain in
the last 12 months. Nevertheless, there was a statistically significant
relationship between age and pain in the last 12 months (P < 0.04). These
variables altogether considerably predict pain and disorder in the last 12
months (R2 = 0.4). Among independent variables, the variables of
education (reverse relationship) and job experience have displayed the highest
amount of tendency.
Table 4: Logistic
regression components and related amounts of pain and discomfort in body parts
in the last 12 months
|
Intercept (B spot) |
Standard error |
Wald statistic |
P-value |
Variable |
|
0.061 |
0.058 |
1.130 |
0.288 |
Body mass index |
|
0.040 |
0.077 |
0.269 |
0.604 |
Age |
|
0.307 |
0.131 |
5.498 |
0.019 |
Job background |
|
-0.472 |
0.340 |
1.934 |
0.164 |
Education |
Discussion
Based
on data analysis, ergonomic risk level, which was measured through REBA method,
was not suitable among the personnel of Rasht Porcelain Company, Iran. In
addition, the frequency of pain in different body parts (waist, hands and
wrists, neck, shoulders, elbows, and etc.) based on the NMQ among the personnel
of Rasht Porcelain Company was high. Based on the JCQ, psychological and mental
occupational factors influencing the prevalence of MSDs were inappropriate in
the studied subjects.
As
the results of the present study indicate, most cases of discomfort of body
parts due to problems such as pain, discomfort, and numbness were related to
the waist. This finding was in agreement with that of a study by Mohammadfam et al. (6). Their research assessed the risk of
MSDs with the use of Postural Loading on the Upper Body Assessment (LUBA) and
QEC method among the employees of an industrial company (6).
The
results of this study showed a statistically significant correlation between
average amounts of age and pain in the last 12 months (P < 0.04, P <
0.05, respectively). Sharafi et al. have come to a
similar conclusion about the correlation between the variable of age and the
frequency of MSDs among the carpet weavers of Sanandaj
City, Iran (7).
In
this study, no significant relationship was found between the two types of hand
dominance (left-handedness and right-handedness) and pain and discomfort. This
finding was in accordance with that of the study by Mehrparvar
et al.(8), who assessed the risk of MSDs based on QEC
method at a food production factory. In addition, this finding is in agreement
with the results of the study by Choobineh et al. at
a tire factory (8).
Frequency
percentage of pain, discomfort, and numbness in the 9 studied body parts during
a 12-month-long survey was, respectively, higher in the waist, hands and
wrists, neck, and shoulder. This finding is in agreement with the findings of
the study by Nogueria et al. on the indicators of psychological
disorders/ problems and MSDs among the workers of the repair and maintenance
unit of an airline using NMQ and JCQ (9).
In
this study, distribution of musculoskeletal problems, which inhibited daily
life activities during the last 49 weeks, was mostly related to the neck,
shoulders, hands and wrists, and waist. This finding was in accordance with the
findings of Alrowayeh et al. (10). They performed a
study on a group of rehabilitation specialists in Kuwait with the use of the
NMQ in order to obtain the frequency of MSDs among this group. In their study,
the most important MSDs were reported to be in the waist, wrists, knees, feet,
and ankles (10).
In
this study, the statistical distribution of job content was found to have a
significant relationship with the body parts in risk of pain, discomfort, and
numbness (P < 0.05). This finding was in agreement with the findings of the
study by Nogueria et al. (9).
On
the basis of statistical distribution, investigation of the level of danger
among the workers through REBA method illustrated that more than half of them
were at the average risk level (63.6%). These workers and the workers of above-mentioned
groups (people “with pain” and people “without pain”) require corrective
actions. This finding was in agreement with the findings of the study by Sumita et al. on the prevalence of MSDs
among Indian dentists based on REBA method. They found that the REBA score was
high and work postures must be corrected (11).
Between
REBA score and the workers’ BMI, no significant statistical relationship was
found and the observed correlation was not noticeably important. This finding (because of kind of work and study population) stands in
contrast to the finding of the study by Sharafi et
al. on the prevalence of MSDs and its relationship to work postures based on
QEC method. They showed that increased BMI is the most important reason for the
high frequency of disorders in the waist area (7).
Based
on regression results, the work experience variable was an appropriate
predictor of work-related injuries during the research period. The variables of
work experience and BMI, respectively, are good predictors of absence from work
due to work-related injuries.
With
the use of regression test, no significant statistical relationship was found
among the variables of age, work experience, education, and BMI and REBA score.
This finding is in accordance with the results of the study by Varmaziar et al. on work postures of medical packaging workers
with the use of the RULA method and Body Map Questionnaire (10). They reported
that there was no correlation between the total RULA score and age, weight, and
work experience.
Suggestions
in this research include:
1.
Due to inappropriate postures (poor range of motion, load lifting, use of
non-ergonomic work tools, and inappropriate work level) in industries, it is
essential to design an appropriate standard work environment based on
ergonomics, safety, and occupational health.
2.
In order to obviate the physical and psychological needs of the employees of
the surveyed industry, it is recommended to reduce the physical and mental
burden on the worker and provide appropriate social welfare services for them.
3.
Based on the REBA method, most of the investigated workers were at an
occupational risk level that required corrective measures; therefore, their
jobs must be prioritized in ergonomics intervention programs.
4. Taking into account the frequency of work-related risk factors
in the process of identifying and evaluating the work environment of the
studied industries, to control risk factors, especially for decreasing and
removing inappropriate postures, the use of a three-level pyramid of control in
order of preference is suggested for engineering, administrative/ executive,
and training tasks/ measures.
5. The results of the present
research illustrated that employees with more work experience were at greater
risk of MSDs.
Conclusion
Evaluation
of work postures and the prevalence of MSDs among the personnel of Rasht
Porcelain Company showed that MSDs among the employees were mostly reported in
the neck, hands and wrists, waist, and knees. Disorders among employees were
due to the nature of their jobs. According to the REBA scores, the most
important reasons for these disorders were inappropriate postures (limited
range of motion, incorrect load carrying, use of non-ergonomic work tools, and
improper work level). The level of physical and psychological needs of these
workers is high, which increases the probability of physical injuries such as
MSDs. In addition, REBA results showed that most of the participants of this
study are in need of corrective actions. This suggests that the employees' work
environment is not ergonomically suitable.
Acknowledgments
This
research was conducted with the help of the professors of the School of
Engineering of Islamic Azad
University. We appreciate the efforts of all those who have cooperated
in conducting this study, especially Dr. Mohammad Imani.
Conflict of interests:
None declared.
Reference
1.
Sahu S, Chattopadhyay
S, Basu k, Paul G. The ergonomic
evaluation of work-related musculoskeletal disorders among construction labourers working in unorganized sectors in West Bengal,
India. J Hum Ergol
2010; 39(2):99-109.
2.
Maulik Sh,
Iqbal R. Occupational health and musculoskeletal
symptoms among Indian Medical Laboratory technicians. Journal of
Occupational Health and Epidemiology 2013; 2(3):82-92.
3.
Maulik S, Iqbal
R, De A, Chandra AM. Evaluation of the working Posture and prevalence of
musculoskeletal symptoms among medical laboratory technicians. J Back Musculoskelet Rehabil 2014;
27(4):453-61.
4.
Punnett L,
Gold J,
Katz JN,
Gore R,
Wegman DH. Ergonomic stressors and
upper extremity musculoskeletal disorders in automobile manufacturing: a one
year fallow up study. Occup Environ Med
2004; 61(8):668-74.
5.
Shizaei M, Mirzaei
R, Khaje-Alizade A, Mohammadi
M. Evaluation
of ergonomic factors and postures that cause muscle pains in dentistry
students’ bodies. J Clin EXP Dent 2015; 7(3):e414-8.
6.
Mohammadfam I, Kianfar A, Afsartala B. Assessment of musculoskeletal disorders in a
Manufacturing company using QEC and LUBA methods and comparison of results.
Iran Occupational Health 2010; 7(1):54-60.
7.
Sharafi N, Gharibi
F, Khoobi J. Prevalence of musculoskeletal
disorders and its relation to working posture in Sanandaj
hand-woven carpet weavers. Scientific Journal of Kurdistan University of
Medical Sciences 2014; 19(4):1-9.
8.
Mehrparvar AH, Ranjbar
S, Mostaghaci M, Salehi M.
Risk assessment of musculoskeletal disorders by QEC method in a food production
factory. Journal of Safety Promotion and Injury
Prevention 2011; 3(2):54-60
9.
Nogueria
HC, Diniz AC, Barbieri DF, Padula RS,
Carregaro RL,
de Oliveira AB. Muscul Skeltal disorders and psychosocial risk factors among
workers of the aircraft maintenance industry. Work 2012; 41(Suppl
1):4801-7.
10.
Alrowayeh HN,
Alshatti TA,
Aljadi SH,
Fares M,
Alshamire MM,
Alwazan SS. Prevalence,
characteristic, and impacts of work-related musculoskeletal disorders: a survey
among physical therapists in the state of Kuwait. BMC Musculoskelet
Disord 2010; 11:116. Doi:10.1186/1471-2474-11-116.
11.
Sumita B, Sameeksha
H, Lalitagauri M. Prevalence of musculoskeletal
disorders among indian
dentists: a pilot survey with assessment by rapid entire body assessment. World
Journal of Dentistry 2015; 6(1):39-44.
12.
Varmaziar S, Safari A, Younesi M. Assessment
of working postures and prevalence of musculoskeletal disorders in between
staff of the packing of medicines by using RULA method and Body map
questionnaire. Paper presented at: The first international conference on ergonomics Iran;
2010 May 7-8; Tehran, Iran.
* Corresponding
author: Ramazan Mirzaei,
Dept. of
Environmental and Occupational Health Engineering, School of Health,
Mashhad University of Medical sciences, Mashhad, Iran
Email:
rammir277@gmail.com