Prevalence of work-related musculoskeletal injuries among South Indian hand screen-printing workers

Abstract

BACKGROUND:

Hand screen-printing (HSP) plays a predominant role in textile industries in developing countries. Workers from HSP industry were mostly affected by musculoskeletal injury due to monotonous, and prolonged work nature and poor workplace environment.

OBJECTIVE:

The present study aims to investigate the prevalence of work-related musculoskeletal disorder (MSD) symptoms and risk factors associated among the HSP industry workers.

METHODS:

Cochran’s sample size for categorical data was used to select 385 HSP workers of 1000 samples from various provinces of Tamil Nadu, INDIA. Modified Nordic based questionnaire was used to assess the musculoskeletal injuries and risk factors among HSP workers.

RESULTS:

The statistical analysis revealed that 62.5% workers are prone to MSD symptoms with lower back (75.1%), shoulder (66.2%), knees (58.7%), and ankle/feet (55.6%). Age, experience, marital status, stress in the job were the risk factors which significantly (p < 0.05) associated with the reported MSDs. Further, this study result infers that the subjects with higher age and experience are exposed higher levels of MSD prevalence of 85.5% and 92.0% respectively in past 12 months than other groups. Among the different work categories in HSP task, the workers reported with the maximum discomfort during printing work (63.1%) with Odds ratio as 10.38 and 95% CI is 6.18–17.4. than the material handling and drying task.

CONCLUSIONS:

Study results infer that HSP workers are prone to lower back and shoulder pain followed by knees and ankle feet regions. Socio-demographic factors, awkward posture and repetitive movements contribute to cause MSD among hand screen-printing workers.

Keywords

Cross-sectional study occupational health ergonomics textile industry musculoskeletal disorder

1 Introduction

Work-related musculoskeletal disorder (WMSD) is one of the most common issues in the workingenvironment and a serious socioeconomic issue in modern society [1, 2]. The World Health Organization had specified multiple risk factors, such as workload pressure; work with deadlines; repetitive movement and work with lower arm support, to cause WMSDs among workers all over the world [3]. WMSDs are caused by forceful exertion, repetitive motion, prolonged standing, long hours of working with awkward postures [4, 5]. On the other hand, high physical demands, insufficient recovery time and poor postures are the major contributing factors to cause Low back pain [6]. Further, WMSDs reduce productivity at work, increase absenteeism, job transfer and decline the work quality [7, 8]. In addition, WMSD would lead to major health problems among workers in developed and developing countries [9, 10]. It has been reported that work-related disorders and occupational injuries were about 15% to 20% in America [11] and it increases the health care cost as well [4]. On the other hand, WMSDs are the powerful cause of disability and serious health implications in public and society [12].

In India, textile based work is one of the major occupations, for which a huge amount of labor force is used [13]. Among various textile-based works, Hand screen-printing (HSP), which involves the manual labors for printing the design on cloth fabric, plays a major role in developing country like India. For example, a small-scale hand screen printing industry workplace consists of five to ten tables with the specification of length 160 feet, breadth 10 feet and height of 3/2.5 feet (Fig. 1). Steel frames with the stencil for various designs, squeegee and coloring dye are the required materials for the printing process. During the entire printing process, the worker performs the task with the standing posture. Employers are mostly from the rural areas and unaware of an ergonomic working environment, workstation design and working postures. Due to the poor ergonomic workplace design and the risk factors such as repetitive movement for both upper and lower extremities, awkward posture led to severe pain on shoulder muscles, knee and ankle/foot and low back region for the workers [14].

Fig.1

Printing and drying process in Hand Screen Printing industries.

To authors knowledge none of the previous studies analyzed the risk factors and cause of MSD’s among the hand screen-printing workers. Studies related to the other similar textile (hand woven carpet) industry, which required extensive labor, reported that the working time; poor workstation design; and constrained working postures as the major risk factors to cause MSDs [15, 16]. This demand us to explore the MSD causes and risk factors associated with the HSP workers. In this paper, we aim to conduct a cross-sectional study among the HSP workers in the western parts of Tamil Nadu, India in order to investigate the work-related MSD and its associated risk factors using the Nordic based Questionnaire. Cross-sectional study, also known as a prevalence study analyzes the problem, in particular groups of the population at a particular point of time by collecting data from the working population [17]. In addition, the Odds ratio is used to describe the probability of each category risk factor to cause MSD among HSP workers.

2 Materials and methods

2.1 Study protocol

This study analyzes MSD among HSP workers using the data collected from July to September2014. The sample size of 385 cases is determined using Cochran’s sample size for categorical data with 95% confidence interval and 5.0% precision level [17]. The study population of mean age 35.08±8.11 (mean±SD), experience of 7.08±5.20 years (mean±SD), and BMI of 23.81±2.56 (mean±SD) prevailed among the workers. Further, male and female workers were equally distributed in this study. To quantify the distribution of pain, the subjects were classified into 4 categories based on age, experience, task and prevalence of MSD. First class is based on their age, this group is further subgroup into 3 group such as group1(G1)–<30 years, group2 (G2)-between 30 to 40 years and group 3(G3) –>40 years. Second, class based on experience was group1(Gx1) –≤5 years, group2 (Gx2) –6 to 15 years, Gx3- >15 years. The third class was performed based on the task such as attaching materials, printing, and drying. The forth class was sub-grouped as with MSD and without an MSD (NON-MSD).

Inclusion criteria for enrolling the subjects were: male and female hand screen printing workers with age greater than 18 years and minimum 1year of HSP work experience. Subjects with a history of fractures (bone fracture in any part of the body due to accidents, excluding those which occurred in the current industry) were excluded from the study. Also, workers with a history of any kind of surgery and chronic diseases such as cardiac disease, diabetes mellitus, high blood pressure were excluded from the study. Prior information and explanation about the study were given to the subjects before the commencement of work. As the workers are multilingual, the study details were explained to each individual orally in their first language and an informal consent form was obtained. The informal concern form was originally written in English and Human Ethics Committee of Kongu Institutions, Tamil Nadu, India approved thesame.

2.2 Data collection

Data was collected using the Nordic based Questionnaire specifically designed for the current study [18]. The questionnaire consists of information on worker background, psychological, illness history and other work-related information. Worker background includes age, gender, marital status, work experience, alcohol and tobacco consumption status. Psychological questions like job satisfaction and job stress; work-related information like working hours, rest time, repetitive motion (for upper and lower extremities, lower back), and awkward posture (for upper and lower extremities, lower back) were also included. The questionnaire also analyzes about the frequency of pain distribution in overall anatomical sites such as the neck, shoulder, upper and lower back, upper and lower extremities. Here, the level of pain was categorized into four as, ‘mild’; ‘moderate’; ‘severe’ with some soreness during work eventually reducing workability and ‘unbearable’ pain which demands off time. Few questions such as consumption of alcohol and tobacco are added in the worker’s background session to understand the relationship between the habitus and WMSDs. In work related section, questions such as frequencies of repetitive motion for upper and lower extremities, and the current work activity that involves awkward posture for anatomical sites and its frequencies are recorded as well. A face to face questionnaire survey was conducted for selected subjects at 41 printing industries located at various parts of Tamil Nadu, India. This survey was performed during the months of July to December 2014.

2.3 Workplace environment

In HSP industry, normally the working hours is maintained at 10 hours per day (9 am –7pm). Workers are provided three break session in the work hours such as two tea breaks about 15 minutes (11–11.15 am and 4–4.15 pm) each and a lunch break for 1 hour (1–2 pm). In hand screen printing, workers involve monotonous repetitive movements for various tasks such as attaching the clothes with the table, printing the design, and drying the clothes. The printing table is 50 m long, 3 m wide and 0.91 m/0.76 m high with 30 degrees of inclination.

(i) Attaching the cloth to the table

Initially, the workers spread the bundled cloth material over the table; this work would be performed by two workers. Once, the cloth material is spread over the table, other workers use ball pins to attach the cloth firmly to the table and make sure it’s wrinkle free. It takes around 45 minutes to complete the process.

(ii) Printing process in Hand screen-printing

Printing process involves of frame lifting and rubber squeegee to force the ink on the cloth as shown in first half of Fig. 1. The stencil frame is 1 m in length and 3 m in breadth, weighs around 5–10 kg. These repeated lifting and place the frame at the desired positions and move the rubber squeegee in standing posture [19, 20].

(iii) Drying the printed cloth materials

Once the printing process is completed, the workers have to climb on the printing table and hang the cloth on the rope tied over the printing table as shown in the second half of Fig. 1.

2.4 Data analysis

The study data was analyzed through SPSS v 20.0. Descriptive statistics such as mean, standard deviation, percentages, and frequencies were used to describe the study variables. The MSD among HSP workers majorly varied with the age and experience. So, to analyze it better, the age and experience group is considered in the present study. The association between the independent variables and reported MSD (dependent variables) was analyzed using chi-square tests and multiple logistic regression analysis with the confident level at 95 percentiles (p < 0.05).

3 Results

The demographic variables such as age, BMI, marital status, education level and work experience of the 385 participants were categorized into different levels as shown in Table 1. The Odds ratio (OR) represents the probability of MSD occurrence comparing to the reference groups. The confidence interval (95% CI) represents the interval level (maximum and minimum) of odds ratio values.

Table 1
Factors associated with WMSDs of HSP workers and OR, 95% CI of reported MSD (n = 385)

Factors n Reported MSD Prevalence (%) OR 95% CI p value

Age

<30 116 34 29.3 1

30–40 131 92 70.2 1.39 1.02–1.89 <0.001

>40 138 118 85.5 3.34 2.18–5.11

BMI

Under weight 36 20 55.5 1

Normal weight 300 189 63.0 0.94 0.69–1.31 >0.05

Overweight 49 35 71.4 1.32 0.83–2.10

Experience

≤5 137 45 32.8 1

6–15 147 106 72.1 1.50 1.11–2.03 <0.001

>15 101 93 92.0 5.91 3.00–11.6

Marital status

Single 70 9 12.8 1

Married 315 235 74.6 5.80 3.14–10.7 <0.001

Stress in job

Low 57 27 47.3 1

Moderate 282 186 65.9 1.28 0.97–1.68 <0.05

High 46 31 67.3 1.14 0.73–1.76

Work related

Variables

Discomfort during

attaching material

No 266 133 50.0 1

Yes 119 111 93.27 1.86 1.63–2.12 <0.001

Discomfort during

printing

No 142 13 9.15 1

Yes 243 231 95.06 10.38 6.18–17.4 <0.001

Discomfort during

drying

No 208 82 40.0 1

Yes 177 162 91.5 2.32 1.95–2.76 <0.001

Factors	n	Reported MSD	Prevalence (%)	OR	95% CI	p value
Age
<30	116	34	29.3	1
30–40	131	92	70.2	1.39	1.02–1.89	<0.001
>40	138	118	85.5	3.34	2.18–5.11
BMI
Under weight	36	20	55.5	1
Normal weight	300	189	63.0	0.94	0.69–1.31	>0.05
Overweight	49	35	71.4	1.32	0.83–2.10
Experience
≤5	137	45	32.8	1
6–15	147	106	72.1	1.50	1.11–2.03	<0.001
>15	101	93	92.0	5.91	3.00–11.6
Marital status
Single	70	9	12.8	1
Married 315	235	74.6	5.80	3.14–10.7	<0.001
Stress in job
Low	57	27	47.3	1
Moderate	282	186	65.9	1.28	0.97–1.68	<0.05
High	46	31	67.3	1.14	0.73–1.76
Work related
Variables
Discomfort during
attaching material
No	266	133	50.0	1
Yes	119	111	93.27	1.86	1.63–2.12	<0.001
Discomfort during
printing
No	142	13	9.15	1
Yes	243	231	95.06	10.38	6.18–17.4	<0.001
Discomfort during
drying
No	208	82	40.0	1
Yes	177	162	91.5	2.32	1.95–2.76	<0.001

Abbreviations: WMSD: Work-Related Musculoskeletal Disorders; HSP: Hand Screen Printing; OR: Odds Ratio; CI: Confidence Interval. P < 0.001, highly significant; p < 0.05, Significant by chi-square test.

3.1 MSD causal analysis (factors associated with work-related musculoskeletal disorders)

The Chi-square test showed significant associations between WMSDs and risk factors for the last 12 months (Table 1). Odds ratio (OR) and 95% CI are used to display the probability of increased amount of MSD with the reference variable in the factors. The Odds ratio for the reported MSD describes, how high the probability is, to cause MSD when compared with the reference groups (NON-MSD or low MSD groups). The Odds Ratio (OR) for the demographic risk factor for G1 of OR and 95% CI was 1.39 and 1.02–1.89 and for G3 was OR of 3.34 and 95% CI was 2.18–5.11. This infers that the probability of causing MSD increases with increase in age (p < 0.001).

Next, the significant risk factor was experience (p < 0.001) in which Gx2 group of 6–15 years of experience, with 95% OR and CI of 1.50, 1.11–2.03, and Gx3 group of 95% OR and CI 5.91, 3.00–11.6. So, the probability of causing MSD increases with the increase in experience. The workers who had reported moderate stressfulness (OR, 95% CI 1.28, 0.97–1.68) had a higher MSD than higher stress workers.

On the other hand, the workers reported discomfort at all the three different tasks such as attaching materials, printing and drying. However, the odds ratio indicates that the probability of MSD for printing activity (OR, 95% CI 10.38, 6.18–17.4) was more than the drying (OR, 95% CI 2.32, 1.95–2.76) and attaching task (OR, 95% CI 1.86, 1.63–2.12).

Figure 2 shows the distribution of demographic and workplace factors for the groups with MSD and without an MSD (NON-MSD). The workers with experience (6–15 years) and (>15 years) were significantly (p < 0.001) fell under the MSD group than the NON-MSD groups, this result was evident that the risk of MSD increases as the experience increases. A similar effect was observed for the age and MSD risk correlation study i.e <30 years’ age group people score was not significant comparing to the MSD group. To be more specific, the age group G2 and G3 were considered, the prevalence in MSD groups was significantly (p < 0.001) higher than the NON-MSD groups. Other factors like marital status, and variables such as discomfort during attaching materials, during printing and drying the materials were also significant (p < 0.001) among the MSD groups than the NON-MSD groups. BMI had a significant effect on the reported MSD. Subjects under overweight category were higher in probability to get the MSD (OR, 95CI 1.32, 0.83–2.10).

Fig.2

Distribution of demographic and work-related risk factors among MSD and NON-MSD groups. ^*Significant, p < 0.05; ^**highly significant, p < 0.001; by Chi-square test.

3.2 Pain analysis (Frequency and distribution of pain in each anatomical site by age and experience)

The prevalence (%) and 95% confidence interval (95% CI) of work related musculoskeletal pain among hand screen-printing workers in different anatomical sites for the past 12 months by the age group were shown in Fig. 3. The MSD results indicate that the higher age group >40 years had a higher MSD of 85.5% than the G1 and G2 of 70.2% and 29.3% respectively. Also, this higher age group reported low back pain (86.23%), shoulder region pain (78.98%), knee pain (63.43%) and ankle/foot pain (68.11%). Pain, over other anatomical sites, was same to all age groups, but there was a difference in the knee and ankle/foot pain between the age group G2 (30–40 years) and G3 (>40 years). Though the age group <30 years reported very low MSD, they experienced pain over low-back (58.62%) and shoulder region (47.41%).

The prevalence (%) and 95% confidence interval (95%) of work related musculoskeletal pain among the hand screen-printing workers in different anatomical sites for previous 12 months by experience group were shown in Fig. 4. The result infers that the Gx3 group has higher MSD of 92.0% than the Gx1 and Gx2 group of 72.1% and 32.8% respectively. Similarly, the higher age group reported low back pain (82.17%), followed by shoulder pain (78.21%), knee pain (73.26) and ankle foot pain (71.28%). In addition, it has been observed from the result that low back pain, shoulder pain, knee pain and ankle foot pain increases reasonably with the increase in experience. The occurrence of other pain was less among the middle experience Gx2 and Gx3 groups (6 to15 years). On the other hand, the Gx1 group individuals experience less pain compared to others.

Fig.3

Prevalence (%) and 95% CI of work-related musculoskeletal pain among hand screen printing workers in different anatomical site for previous 12 months by age groups (n = 385). Note: 95% CI marked as label on each column; MSD-Musculoskeletal disorder.

Fig.4

Prevalence (%) and 95% CI of work-related musculoskeletal pain among hand screen printing workers in different anatomical site for previous 12 months by experience groups (n = 385). Note: 95% CI marked as label on each column, MSD-Musculoskeletal disorder.

In addition, the anatomical sites pain score as shown in Table 2 indicates that about 40% of the individuals have reported moderate pain and over 50% of the population have severe pain with some discomfort hindrance to performing regular tasks. However, very few have reported unbearable pain over the considered anatomical sites in which low back and upper extremity secured the top spots.

Table 2

Level of MSD experienced by the MSD reported groups

Levels of MSD	Rep. Mild pain or	Rep. Moderate	Rep. Severe pain	Rep. Unbearable
	discomfort (%)	pain with no	with reduction in	pain requiring
		reduction in	activity (%)	time off work (%)
Anatomical sites		activity (%)
Neck	1 (1.0)	32 (33.6)	53 (55.7)	9 (9.4)
Shoulder	10 (4.9)	82 (40.3)	101 (49.7)	10 (4.9)
Elbow	4 (4.3)	37 (40.6)	41 (45.0)	9 (9.8)
Wrist	9 (11.2)	26 (32.5)	39 (48.7)	6 (7.5)
Upper back	8 (8.3)	35 (36.4)	32 (33.3)	21 (21.8)
Lower back	10 (4.6)	79 (36.4)	106 (48.8)	22 (10.1)
Hip	5 (5.4)	34 (36.9)	47 (51.0)	6 (6.5)
Knees	13 (7.0)	67 (36.4)	90 (48.9)	14 (7.6)
Ankle/feet	16 (8.9)	66 (36.8)	84 (46.9)	13 (7.2)

4 Discussion

This study investigates the risk factors associated with the work and the work-related musculoskeletal disorders caused for the individuals who work in the hand-screen printing industries in the western part of Tamil Nadu, India. Few previous studies such as women rebar workers, sugarcane farmers, and mine workers had demonstrated that these groups of workers are prone to MSD [19 , 22]. The current study, results infer that 62.5% of workers are prone to MSD. This finding was higher than the prevalence of MSD among women rebar workers (57.7%) [19] and underground mine workers in Zambia (42.6%) [21]. However, it is lower than the prevalence of MSDs among sugarcane farmers (88.70%) in Thailand [22], home-based garment workers of 76.7% [23]. This variation might be due to the different workstation, work environment and tools used. Further, examination of HSP worker towards the pain prevalence spread in various anatomical sites infer that low back pain score was highest with 75.1%, shoulder region of 66.2%, knees of 58.7%, ankle/feet with 55.6%, elbow pain of 29.6%, hip pain score of 27.8%, upper back with 28.8%, and wrist pain score as 24.7%. Thus the results revealed that prevalence of lower back and shoulder were higher than the palm plantation farmers (40, 19% respectively) [24] but less than the factory workers in Nigeria (85.71, 37.14% respectively) [25]. The discomfort feeling in the lower back may be due to the awkward posture with repetitiveness for a prolonged time. Current study results are in-line with the previous finding [26, 27], where, it was reported that severe flexion and bending was found to be significantly related to lower back pain. In addition, National Institute for Occupational Safety and Health review reported that there was a strong association between the low back disorders and the awkward postures [28 –30]. Thus, it is evident that HSP workers have high low back pain due to the awaked standing posture and printing task that demands the monotones and repetitive flexion.

Further investigating the MSD scores with respect to age (Fig. 3) result reported by G3 group (>40 years) shows higher (85.5%) than the other two age groups, this result is supported with Shankar et al. [31, 32] finding. In addition, it is observed that the Gx3 experiences group MSD scores were higher (92.0%) than Gx2 group of 72.1% and Gx1 group (≤5 years) of 32.8% (Fig. 4). This MSD scores based on experiences results is also in-line with Suda et al. [19] demonstration of MSD increases with the increase in work experiences. The second-high prevalence is found in the shoulder region (66.2%). According to Silverstein et al. [33] if a work involves greater than 50% of the total work cycle this action is said to be repetitive. The hand screen printing workers repetitively wipe on the screens using squeegee blade and frequently lift and shift the screens above the table during the printing work. The repetitiveness and lifting with awkward posture cause the high prevalence of MSD in the shoulder. These findings are in line with the finding of Armstrong and Silverstein [34] and Gangopadhyay et. al. [35] which specified that repetition in the job, extension and forceful exertion for long period results in upper limb and shoulder disorders.

Finally, the third high prevalence is showed on the lower extremity that constitutes knee (58.7%) and ankle/feet region (55.6%). The subjects performed different works, such as attaching the cloth material with table, printing and drying process, with standing posture and repetitive movement for more than 10 hours similar to the rice farmers of West Bengal [36]. In addition, the result also reveals that the knee pain constantly increases with increase in age (Fig. 3). This was consistent with Felson et al. [37], Jensen et al. [38], and metal workers in Bangladesh, where awkward posture and repetitive movements were significantly related to musculoskeletal symptoms [39]. Prolonged standing with frequent repetitiveness was the major cause for MSD in knee and ankle/foot. Most of the subjects belonging to the MSD group reported third severity level –severe pain with the reduction in activity.

This result infers that the HSP worker has the most frequent site of severe pain in the regions such as the hip, lower back, neck and shoulder. This might be due to a) The upper extremity and low back pain could be induced by the repeated lifting and place the frame at the desired positions and move the rubber squeegee by maintaining awkward posture b) the process of climbing on the table for drying task could have contributed to the knee and foot pain to the workers. This issue could be addressed by means of cultivating the ergonomics to the worker and by means of redesigning the workplace environment. It has been reported and accepted that the musculoskeletal disorder among the workers in an industrial environment can be reduced by providing proper ergonomic workstation design [40]. Thus, by minimizing the risk factors through the proper ergonomic work intervention in HSP industry would be our future workfocus.

This study findings mostly depend on participants understanding of the working environment and nature of tasks; this may lead to the following limitation a) worker’s health history and present status depends on their capacity to recollect or their level of awareness b) data was collected on a controlled locality, that could influence the findings reliability. However, above limitations has not affected or biased the finding as we have not concluded the study results based on the health information alone. Further, even though the study population is limited to the particular geographical region, the nature of work examined is universal and thus the finding would guide the entire community of hand screen printingindustries.

5 Conclusions

The study revealed that the hand screen-printing workers are prone to high musculoskeletal pain in the lower back region followed by shoulder, knee and ankle/feet regions. Further, Nordic Questionnaire and statistical analysis of current study results have demanded the need to extend the work further towards to reduce the findings, risk factors with the help of ergonomic redesign of work place and design tools. This redesign might be targeted towards the redesign of the printing table, squeegee, and steel stencil frame to minimize the awkward posture of the lower back of workers and to minimize the discomfort due to lifting respectively.

Conflict of interest

None to report.

Funding

The author(s) disclosed receipt of the following financial support for the research, and authorship for this article: This study was funded by Science Engineering and Research Board (SERB) Department of Science and Technology, India, through Fast Track Young Scientist Scheme Research Project (Ref. No. SB/FTP/ETA-343/2013).

Footnotes

Acknowledgments

The authors would like to acknowledge the printing industry managers, and workers participating in this study for valuable assistance and patiently reporting during their working hours.

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