|Year : 2013 | Volume
| Issue : 2 | Page : 71-75
Prevalence of musculoskeletal disorders among brick kiln workers in rural Southern India
Leeberk Raja Inbaraj1, Obed John Haebar1, Fenn Saj1, Samantha Dawson1, Peter Paul1, Abhilash Kundavaram Paul Prabhakar2, Venkata Raghava Mohan1, Reginald George Alex2
1 Department of Community Health, Christian Medical College, Vellore, Tamil Nadu, India
2 Department of Medicine unit IV, Christian Medical College, Vellore, Tamil Nadu, India
|Date of Web Publication||17-Dec-2013|
Reginald George Alex
Department of Medicine unit IV, Christian Medical College, Vellore - 632 004, Tamil Nadu
Source of Support: None, Conflict of Interest: None
Background: A variety of musculoskeletal disorders and discomfort are seen among brick kiln workers, where heavy physical work is associated with awkward working postures and manual handling of materials, leading to significant morbidity. Materials and Methods: This cross-sectional study was conducted in unorganized brick kiln industries in villages of Vellore district of Tamil Nadu and included 310 brick kiln workers. Modified Nordic Questionnaire was used to survey the prevalence of musculoskeletal disorders and the intensity of pain was assessed by the body pain discomfort scale. Results: The mean age of the workers was 37 13.2 years with a range of 18-85 years. 62% (n = 192) had normal body mass index, whereas 27% (n = 85) were undernourished. The commonest posture adopted at work was squatting (67%) followed by standing (14%). Majority of workers (87%, n = 269) reported to having symptoms of pain currently of which 51% (n = 158) had pain during work. Chronic low back ache (LBA) (1 year prevalence -59%) and acute LBA (1 week prevalence-33%) were the commonest followed by chronic knee pain. More than 10 years of work was significantly associated (P < 0.05) with acute LBA and acute and chronic knee pain. Severity of the pain was also significantly (t statistic 2.476, P < 0.05) associated with job dissatisfaction. Conclusion: Long-term brick kiln workers, who adopt a specific posture for prolonged periods, have severe musculoskeletal pain that interferes with activities of daily living and reduces job satisfaction. Health education on frequent postural change, implementation and monitoring of laws among unorganized industries are recommended to bring down morbidity due to musculoskeletal disorders (MSD).
Keywords: Brick kiln workers, low back pain, musculoskeletal disorders
|How to cite this article:|
Inbaraj LR, Haebar OJ, Saj F, Dawson S, Paul P, Prabhakar AP, Mohan VR, Alex RG. Prevalence of musculoskeletal disorders among brick kiln workers in rural Southern India. Indian J Occup Environ Med 2013;17:71-5
|How to cite this URL:|
Inbaraj LR, Haebar OJ, Saj F, Dawson S, Paul P, Prabhakar AP, Mohan VR, Alex RG. Prevalence of musculoskeletal disorders among brick kiln workers in rural Southern India. Indian J Occup Environ Med [serial online] 2013 [cited 2019 Apr 20];17:71-5. Available from: http://www.ijoem.com/text.asp?2013/17/2/71/123170
| Introduction|| |
Musculoskeletal disorders (MSDs) are prevalent among workers in the construction industry which warrants heavy physical work, often necessitating inappropriate working postures for prolonged periods, which significantly increases morbidity and considerably decreases the work ability.  The brick manufacturing industry in India, the second largest in the world following China, falls under the above-mentioned category, where the majority of the workforce is part of the unorganized sector, comprising mostly of migrant workers including men, women, and in some cases, even children.  In contrast to other occupational disorders which could be attributed to occupational exposures to toxic substances, MSD among brick kiln workers owes its pathophysiology to unorthodox postures opted by these workers, where the joints and muscles are held in unconducive physiological positions for protracted periods of time, in suboptimal working conditions.  The manufacture of bricks begins with mining, preparation, and molding of clay, followed by drying and burning of bricks, after which they are arranged in a prescribed fashion for transport. Prior research in this area has identified that poor working conditions, suboptimal physiological postures that compel frequent bending and twisting, and inadequate rest-breaks are among the risk factors for MSD among these workers.  These musculoskeletal disorders take a toll on their lives by affecting their activities of daily living (ADL), leading to slow economic growth of their families resulting in poor overall quality of life. Brick kiln workers who comprise a part of the unorganized work sector in rural India are in a disadvantageous position and literature regarding their health problems and needs are largely unavailable. This study was done with a threefold aim of assessing the prevalence of MSD among brick kiln workers in rural Tamil Nadu, to identify common postures adopted by them during the course of their work, and to measure the intensity of pain among the workers in brick kilns.
| Materials and Methods|| |
This cross-sectional study was conducted among unorganized brick kiln workers in the villages of Vellore district in Tamil Nadu. Mettuedyanpatti, Puthur, Munjurpet villages in Kaniyambadi block of Vellore district, where brick making is the prime occupation. Three hundred and ten participants who were involved in brick making for more than 1 year were included for the study after an initial verbal screening, by exhaustive sampling technique. Sample size was calculated using 1 week prevalence of low back pain 20% with 5% absolute precision.  Individuals with known systemic diseases involving musculoskeletal system such as rheumatoid arthritis, Sjogren's syndrome, and cervical spondylosis were excluded from the study. An iinterviewer-administered and structured questionnaire was used which included basic anthropometric and personal data, details of the common postures adopted during work, duration of work, symptoms of musculoskeletal involvement, and the various joints affected. The questions about musculoskeletal symptoms were adopted from the modified Nordic Questionnaire.  The severity and and intensity of pain was assessed by the body part discomfort scale (Jacqueline et al., 1994). A questionnaire was developed in English and then translated to the vernacular (Tamil), which was pilot-tested among a similar population. An informed written consent was taken before the verbal administration of the questionnaire. Data were analyzed using the Statistical Package of Social Sciences (SPSS Version 16.0). Descriptive data are given as mean (standard deviation [SD]), or as median (range). The association of duration of work to the severity was analyzed by univariate and multivariate logistic regression and their 95% confidence intervals (CIs) were calculated. For all tests, a two-sided P value of 0.05 or less was considered statistically significant. This study was approved by the Institutional Research Board of Christian Medical College, Vellore and the confidentiality of the participants during the study and the analytical phase was maintained using unique identifiers.
| Results|| |
The brick kiln workers recruited for this study were from the villages of Munjurpet (61%), Puttur (37%), and Mettuediampatty (2%). There was a male predominance (55%). The mean age was 37 ± 13.2 years with a range of 18-85 years. Majority of the workers 62% (n = 192) had a normal body mass index (BMI), whereas 27% (n = 85) were found to be undernourished with a BMI of < 18. Most of the women were in the reproductive age group, with only 23% (32/139) being post-menopausal as shown in [Table 1].
A total of 64% (64%) of the workers had been in the brick manufacturing occupation for more than 10 years. Approximately half of them (47.4%) worked for 6-7 days per week, and another 47.4% worked between 3 and 5 days per week as shown in [Table 2]. About one third of the workers worked overtime for >10 h per day. The common postures adopted during majority of the working time were squatting (67%), stooping (19%), and standing (14%). History of trauma that could have contributed to the MSD was elicited in a minority (14%) of the workers. Majority of the study subjects (87%) experienced some kind of pain, with more than half of them (51%) having pain during work. A total of 65% of them had either moderate or severe form of pain when assessed with the body pain discomfort scale. During last 12 months, 59% (n = 183) of the workers had low back pain and 45% (n = 139) had knee pain. The sites, frequency, and distribution of chronic pain are shown in [Table 3]. ADL were affected in 13% of those with low back pain and in 10% of those with knee pain. Workers employed for more than 10 years had a higher incidence of chronic back pain (66.55% vs. 45.5%; P =< 0.05) and chronic knee pain (56% vs. 24.5%; P =< 0.05) when compared to those employed for less than 10 years and these differences were statistically significant with P < 0.05 and higher odd's ratio as shown in [Table 4].
|Table 4: Days at work in a week and years of service and presence of musculoskeletal pain|
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These workers also had significantly higher odds of suffering from acute (1 week) low back pain [odds ratio (OR): 2.28 (95% CI 1.27-4.09), P < 0.05)] and acute knee pain [OR: 3.26 (95% CI 1.57-6.71), P < 0.05]. Workers employed for more than 10 years had 3.11 times higher odds of suffering from either moderate or severe form of musculoskeletal pain (95% CI 1.78-5.66; P =< 0.05).
Approximately, one fourth of them use some form of topical analgesics (24.2%) as self-medication for pain relief, while another quarter of them preferred only rest for pain relief. Nearly, 30% use various forms of oral or injectable analgesics available over pharmacy counters. Those who had severe or moderate form of pain had lower mean score (7.57, SD −2.28) in the visual analogue scale on job satisfaction (P <0.05, t statistic 2.476) than those with mild pain (6.80, SD −2.22).
| Discussion|| |
As per the Economic Survey 2007-08 out of 440 million workers in India, 93% of the workers are in the unorganized sector.  The contributions made by the unorganized sector to the national income are very substantial as compared with that of the organized sector.  A subcommittee of the National Commission for Enterprises in the Unorganized Sector in 2012 estimated that the contribution of unorganized sector to Gross Domestic Product is about 53.9%.  Brick kiln industry is one such sector where the workers are prone for a variety of MSD due to the stressful work posturing and heavy unregulated work load. This is further compounded by physical discomforts at the work place and poor access to health care. Workers earn money depending on how many bricks they make and not how many hours they work. As the workers adopt a constant posture for many hours at a stretch, they are at risk for developing severe musculoskeletal pain which invariably reduces work efficiency and output. Work-related MSD includes inflammatory and degenerative processes that may involve the muscles, tendons, cartilages and joints, causing pain and functional impairment.  Though our study had male predominance, the high also involved in brick making industry, signifying the way of living in the rural setting. Moreover, the unorganized brick kiln industry is a cottage industry in rural areas, where the entire family is involved to sustain their livelihood. In our study, majority of women (70%) reported some kind of pain. As most of these women (67%) were in the reproductive age group and going through physiological events such as menstruation, child birth, they were more vulnerable to pain than men. This may be possible confounders which are challenging to measure. A significant proportion of our workers (27%, n = 72) were malnourished which reflects their poverty and low economic status. As more than 75% (n = 55) of the malnourished workers experience either moderate or severe form of pain, their productivity at work is likely to be affected.
Even though the majority of the workers in our study were employed for more than 10 years, they have no coverage of social security and have to spend out of their meager incomes for all contingencies such as illnesses and children's education. In their old age they are helpless and none of the provisions under the Unorganized Workers' Social Security Act of 2008 are implemented at their work place. The Act has provisions for life and disability cover, health and maternity benefits, old age protection, and recommends suitable welfare schemes such as provident fund, employment injury benefit, and housing, and so on for unorganized workers.  Though regulations on maximum working hours and entitled leave do exist, workers in our study were made to work overtime due to the continuous demand to meet the target number of bricks for the week or month.
Handling raw materials with hands in manufacturing industries which involve bent and/or twisted postures are recognized risk factors for back pain. , This is specifically evident in industrially developing countries, where manual materials handling is inherent within industry with manual labour involved in physically demanding tasks is a dominant factor.  In the present study, the job of the brick makers was described as rather physically demanding, involving frequent twisting and bending of the trunk. This type of job was also described as highly repetitive and requiring high concentration to arrange alternating brick faces in each row. Therefore, workers must pay constant attention to brick orientation and this may impose more stress and increased mental fatigue. Most participants in this study belonged to families with 3 or 4 members who also involved themselves in various stages of the brick making process. So it is difficult to comment on which posture is directly related to the musculoskeletal disorders. However, squatting is the most common posture adopted by the workers at work, since the maximum time is taken for molding the brick followed by mixing the clay. This requires trunk twisting and bending forward for an extended periods of time. This was evident from our study when pain per body region was measured for the past 12 months and 7 days. Our study revealed that most workers complained of low back pain followed by knee pain. Chung and Kee  from Korea also reported that 78.5% of the workers performing tasks that require trunk twisting experienced low back pain, while 55.6% performing tasks that do not require trunk twisting experienced low back pain. Low back ache was the most common pain among the brick makers in other studies from West Bengal, Jharkhand, and Nigeria. ,, This is probably due to repeated bending and twisting of the trunk which causes an enormous force generation at the lumbosacral segment of the vertebral column. 
Neck and upper limb pain were reported in a significant number of brick workers in some studies. ,, We found only a minority of our workers suffering from neck (11.3%, 35/310) and upper limb pain, while the knee joint was the second most affected joint. This could be attributed to the commonly adopted postures in our study population, which is squatting, followed by standing for moulding and clay making. Clay making and moulding work is an important activity, which decides the quality and finish of bricks, which requires hard and long hours of work in similar positions and postures. These postures can affect soft tissues such as muscles, ligaments, and spinal discs. Squatting exerts great pressure on different body parts such as the leg, knee, thigh, back, spinal cord, and on the shoulder and feet as well. This posture can lead to contact stress on the popliteal fold (back of the knees) and pooling of blood in the feet. They can also cause fatigue and discomfort, placing the worker at risk of developing a work related MSD.
Many of the studies conducted in various industries where manual labourers are involved in strenuous work have shown positive correlations between MSD and common postures adopted at work. In a study done at a fish processing industry in Ghana, where workers were involved in heavy manual handling, trunk flexion and/or twisting, pushing, pulling, and lifting weights from below the ground level, neck and upper limb problems were found to be predominant.  Similarly, an Indian study among forging workers showed that operators working in an inadequate working environment with awkward postures, have a high risk of development of musculoskeletal disorders.  Our study also reveals that most of the workers experience pain during work (51%, 158/310), which may cause discomfort, fatigue, and eventually lead to lesser production and earning. Those who experience severe or moderate form (64.8%, 201/310) of pain also seem to be less satisfied with their work, and this may have psychological impact on the quality of life.
A study which examined changes in general health and time with back and neck pain, identified predictors of any such changes.  The study showed that there was a significant decline in general health and significant increase in time with neck pain and back pain. They concluded the predictors of changes in these outcomes were mainly work-related variables such as job interference with family, work-related psychological demands, job influence, and hours worked. Heuer et al.,  found that musculoskeletal complaints among bricklayers decreased with the length of employment. Further investigation revealed this was most likely due to a ''healthy worker effect'' where individuals' susceptible to musculoskeletal complaints leave the trade, leaving their more resilient colleagues in the workforce. This is an important phenomenon to be considered while attempting to assess morbidity among the workers in the unorganized sector. Our study is a community-based study with adequate sample size and used validated tools to measure MSD. However, the limitations are the lack of postural analysis and non-assessment of some of the confounders such as domestic activities.
| Conclusion|| |
This study shows that awkward postures adopted by brick kiln workers during work are directly related to their MSD, which also affect their ADL. Prolonged years at service and overwork also have significant impact on the prevalence of MSD. This study recommends detailed research, health education to the workers, implementation and monitoring of laws in unorganized sectors to tackle morbidity related to MSDs.
| Acknowledgment|| |
- Mr. Sam, Occupational Therapist, Christian Medical College, Vellore, India.
- Dr. Nishanth Arulappan. Medical Officer, Lady Wellington Hospital, Manali, India.
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[Table 1], [Table 2], [Table 3], [Table 4]