Musculoskeletal disorders and their influence on the quality of life of the dockworker: A cross-sectional study

Abstract

BACKGROUND:

Dockworkers are subjected to intense physical labor which leads to frequent occurrence of musculoskeletal disorders.

OBJECTIVE:

This study aims to measure the prevalence of work-related musculoskeletal disorders (WMSD) of temporary dockworkers and its influence on their quality of life.

METHODS:

This was a cross-sectional study developed with temporary dockworkers in Brazil. Recruitment was done by inviting workers when they presented themselves for work at the trade union. The Nordic Musculoskeletal Questionnaire and the Short-Form Health Survey were used. The association between the outcome and the different investigated factors was analyzed through Poisson Regression with robust variance. The Mann-Whitney test was used to compare the data from the Short-Form Health Survey scale among the groups both with and without work-related musculoskeletal disorders.

RESULTS:

The sample was composed of 318 temporary dockworkers with a mean age of 48 years. WMSD prevalence was 37.4%. WMSD was associated with not practicing physical activity (PR = 2.03; p = 0.005), participation in housework (PR = 1.88; p = 0.029), taking care of preschool children (PR = 1.65; p < 0.000) and handling heavy objects (PR = 1.83; p = 0.007). The lumbar spine was the most frequently mentioned area of the body (22.5%) in the WMSD analysis. Workers without WMSD had higher (p < 0.00) quality of life scale scores in relation to functional capacity, physical and social aspects, pain and vitality.

CONCLUSIONS:

The results highlight the relevance of developing action plans regarding the needs of this specific population of workers, especially concerning the reduction of risk factors.

Keywords

Occupational health work-related musculoskeletal disorders cumulative trauma disorders

1 Background

Concern towards health promotion has increasingly gained importance; its influence in terms of the organization of health systems is noticed throughout the world [1]. In terms of occupational health, physical and mental overload and, therefore, work-related musculoskeletal disorders (WMSD) may increase, causing different levels of functional incapacity. This is considered to be a serious problem [2].

WMSDs are responsible for most absence from work and the high costs involving the payment of indemnities as well as the expenses associated with treatment and work reintegration processes [2]. Data from the International Labor Organization (ILO) in Brazil show around 4% of the world’s gross domestic product is applied to costs of injuries, deaths and diseases per working days lost per year [3]. In 2002, in Brazil alone, ILO reports that 15.029 workers are permanently disabled because of occupational diseases in which WMSDs are the most prevalent [4].

In the context of people’s quality of life, a safe and healthy work environment is essential, as it protects the workers from threats to their health and, simultaneously, expands the capacity of productivity [5, 6]. The physical environment linked to some organizational and psychosocial factors may negatively interfere with the work environment [7]. These problems cause conflicts related to overload, work pressure associated with the fear of losing their jobs and physical discomfort resulting in dissatisfaction, diseases, occupational accidents and compromised mental health [5 , 8].

There are a growing number of workers suffering from musculoskeletal disorders. It is believed that the development of WMSDs is multifactorial and several risk factors which can lead to the appearance of the disease must be taken into account. These can be divided into predisposing factors (genetic, physical, hormonal, anatomical regions exposed to injury and others) and trigger factors (biomechanical, organizational and social) [7, 9]. Some reasons for this increase in the registration of these diseases are the increase in activities which require quick movements, extremely repetitive activities, whereby postures involving great physical exertion cause serious occupational diseases. Because of this, government bodies are increasingly concerned with disseminating and pressuring companies to comply with the protective standards for their employees’ health in order to alleviate diseases [9].

Musculoskeletal symptoms range from minor discomfort that may persist, worsen or lead to serious disabling injuries and job loss. These lesions may present themselves in various ways, either as musculotendinous such as motor dysfunctions or as nerve compressions. If detected early, all of them can receive effective treatment [2]. Musculoskeletal disorders, today, are the most frequent work-related health problems, assuming global proportions regardless of the degree of industrialization of the country and appearing as the second cause of absence from work in Brazil [10].

However, the health conditions resulting from effort required to perform the activities inherent to the duties of these workers are still not known. This study aims to measure the prevalence of work-related musculoskeletal disorders of temporary dockworkers and its influence on their quality of life.

2 Methods

This cross-sectional study was developed with 318 temporary dockworkers from a city in Brazil. The sample respected the proportion and the representation of each class of temporary dockworkers: Stevedores (29.9%), capatazia (port workers) (6.9%), capatazia (organizers) (47.5%), tally clerks (6.3%), watchmen (4.1%), block gangs (3.1%) and coopers (2.2%).

Sample size was calculated considering a 95% confidence level, 2.0 relative risk and a desired statistical power of 80%. The prevalence of musculoskeletal disorders was considered to be 23.3% [11] and 10% was added to compensate for possible target population losses. It was therefore defined that a sample of 318 temporary dockworkers would be necessary.

Two questionnaires that had already been validated in Brazil were used for data-gathering. The Nordic Musculoskeletal Questionnaire (NMQ) was administered to investigate musculoskeletal disorders [12]. Quality of life was evaluated with the Short-Form Health Survey (SF-36) [13]. These two instruments were incorporated as part of a larger questionnaire that also investigated other variables of interest in order to measure the prevalence of work-related musculoskeletal disorders of temporary dockworkers and its influence on their quality of life.

The main outcome analyzed was work-related musculoskeletal disorders. The variables which, according to a literature review, started to constitute a hierarchical theoretical model of risk determination for work-related musculoskeletal disorders are presented in four levels: 1st level –social economic and demographic conditions; 2nd level –lifestyle and biological characteristics; 3rd level –work characteristics; 4th level –health complaints.

Quality control was ensured by the continuous supervision of the field work and daily questionnaire review checking for questions left blank. Double data entry was also performed followed by data evaluation and consistency analysis to detect possible problems in data recording and to correct in order to avoid analysis errors.

The ethical principles for research activities involving human beings as established by National Health Council Resolution 466/2012 [14] were complied with. The participating temporary dockworkers were required to sign a Statement of Consent in which they are guaranteed the necessary explanations concerning the research purpose and anonymity. The study was previously submitted and approved by the Health Area Research Ethics Committee of the Federal University of Rio Grande (Brazil). The dockworkers were randomly recruited to answer the questionnaire when they reported for work at the trade union sheds at the start of the different shifts and in relation different jobs they perform. Care was taken to obtain a mixture of the four work shifts (morning, afternoon, evening and early morning) until the calculated sample size was attained. Care was also taken to ensure the representativeness of each shift, given that some workers prefer to work more at night while others prefer to work in the afternoon, in view of the fact that they are free to make this choice, respecting the working hours established foreach shift.

The data collected was entered twice using an EPI INFO 6.04d template. The analysis was performed by using STATA 10.0 divided into three phases. In the first phase a descriptive analysis of the sample characterization was made with the distribution of frequencies of the various variables.

In the second phase, the factors related to the main outcome (work-related musculoskeletal disorders) were identified. Poisson Regression with robust variance was used to perform the multivariate analysis and estimates of prevalence ratios and their respective confidence intervals (95%). The “p” value was obtained through the Wald test.

The multivariate analysis was done according to the hierarchy of the interdependence analysis model between the variables. Each variable level was gradually analyzed, step by step, starting with the first level. All explanatory variables with a p-value of 0.20 or less were included in the multivariable models.

In the third phase, the workers were divided according to the presence of work-related musculoskeletal disorders and compared in relation to the different scales identified by the quality of life instrument. For the data analysis concerning the quality of life, pre-existing specific SF-36 scales were followed. The Mann-Whitney test was used to compare the data from the different SF-36 scales between the groups with or without work-related musculoskeletal disorders.

3 Results

The study sample was composed of 318 randomly chosen temporary dockworkers respecting the proportion of each job performed in each separate type of dock work, namely 95 stevedores, 22 capatazia (port workers), 151 capatazia (organizers), 20 tally clerks, 13 watchmen, 10 block gangs and 7 coopers. The sample was comprised only of males ranging in age from 26 to 80 years old and having a mean age of 48.

The socioeconomic and demographic characteristics of the sample are shown in Table 1. The analysis showed that 70.4% of workers were overweight or obese (Table 1).

The results showed that 78.6% of the workers did not engage in physical activity at least three times per week for at least 30 minutes.

The findings revealed 29.2% of the workers evaluated have been working at the port for more than 30 years. Considering the total number of working hours, we concluded that most (74.5%) worked 8 hours or less per day, 21.1% between 9 and 10 hours and 4.4% worked more than 10 hours every day. About 6.3% of the temporary dockworkers mentioned having another paid job apart from the temporary work at the port.

With regard to health complaints, 71.7% of the workers had had at least one medical diagnosis since they started working at the port, the most prevalent being fractures (36.5%, e.g. hands and foot) and hypertension (28.0%) followed by tendonitis (15.7%), herniated disc (9.1%) and bursitis (5.7%).

The prevalence of work-related musculoskeletal disorders was 37.4%. When all the different categories are considered, the following proportion was observed in terms of temporary dockworkers with WMSD: Stevedores (38.9%), capatazia (port workers) (22.7%), capatazia (organizers) (43.0%), tally clerks (25.0%), watchmen (15.4%), block gangs (20.0%) and coopers (42.9%).

In the crude and adjusted analysis, none of the first level variables was associated with the outcome. Analysis of the 2nd level of the hierarchical model showed that not practicing physical activity is presented as a risk factor for the occurrence of work-related musculoskeletal disorders (PR = 2.03, p = 0.005). At the same level of analysis other risk factors for WMSD were helping with household activities (PR = 1.88, p = 0.029) and participating in the care of children of preschool age (PR = 1.65, p = 0.000). Computer use outside working hours remained in the multivariate analysis model (p < 0.2) but showed no association with theoutcome.

In the third level analysis, the handling of heavy objects was seen to be related to the outcome, thus increasing the risk of WMSD (PR = 1.83; p = 0.007). No association was noticed between the outcome and the fourth level variables. (Table 2)

In terms of the painful symptoms referred to by the temporary dockworkers according to parts of the anatomical regions, stevedores and capatazia (organizers) were seen to be those who reported painful processes in all anatomical regions. Working with stowage was more frequently related to shoulder overload (15.8%) as well as hip/lower regions (12.6%), the lumbar region (22.5%) followed by the shoulders (15.2%) reported by the capatazia (organizers) as being the body parts most affected by pain (Table 3).

With regard to the quality of life scales listed by the SF-36 questionnaire, a connection between work-related musculoskeletal disorders and the following scales was observed: Functional capacity (p≤0.00), physical aspects (p≤0.00), social aspects (p≤0.00), pain (p≤0.00) and vitality (p≤0.00). Only emotional aspects (p≤0.26), mental health (p≤0.07) and general health status (p≤0.10) did not show any significant connection to the work-related musculoskeletal disorder outcome (Table 4).

4 Discussion

This study aimed to analyze the occurrence of musculoskeletal disorders and associated factors in a group of temporary dockworkers and their influence on quality of life. This is a group of workers with a large average age variation. This aspect, combined with the fact that the different categories which involve these temporary dockworkers have no regular employment makes this group a very heterogeneous one. In addition, it is important to mention that although there is a Workforce Mediation Body to mediate the service between the companies and the workers, these temporary dockworkers are free to show up for work or not, regardless of their health.

The high index of overweight/obesity (70.4%) is higher than in findings in studies with other professional categories –42.9% among electricians in the state of São Paulo/Brazil and 40.2% among workers at an oil refinery in Bahia/Brazil [15, 16]. This condition of being overweight is very high and may show lack of port worker care with nutritional aspects. This condition is aggravated by non-practice of physical activity identified in 78.6% of the workers. This reality exposes these workers to several health risks, ultimately increasing the risk of chronic diseases such as heart problems and diabetes in addition to directly affecting their muscular and cardiorespiratory strength [17, 18]. All of these are changes that affect the performance of labor activities, especially those which demand constant effort as is the case of these temporary dockworkers.

Apart from musculoskeletal disorders, hypertension (28.0%) is also an important finding among these workers, as it was identified as a health risk factor in 10% of the stevedores at the Port of Mucuripe in Fortaleza/CE/Brazil [11]. It is important to take into consideration that hypertension, as well as overweight/obesity and other comorbities, or even physical factors in the working environment, can be related to the stress to which these workers are submitted at work and may, therefore, contribute to the development of musculoskeletal disorders.

The prevalence of health problems referred to by these workers (71.7%) since they started working at the port is relevant. Fracture rates (36.5%) suggest high occupational risk among port workers. Such data confirm the perception that the dockworkers themselves are aware of the existence of health risks in their work environment [19]. Tendonitis (15.7%) and bursitis (5.7%) have also been reported although less frequently. In a study with patients assisted at a Unified Health System (SUS) occupational health service in Belo Horizonte/MG/Brazil, tendonitis reached a level of 49.0% while bursitis 6.0%) was equivalent to the levels highlighted in this study [20]. It is possible that the lower number of cases of tendonitis observed in the present research is due to a wide range of activities done by the temporary dockworkers which may not characterize the repeated movements of the same muscles that trigger tendonitis.

This study showed 37.4% work-related musculoskeletal disorder prevalence, and this number is higher than the 23.3% seen among stevedores in a study conducted at another Brazilian port [11]. It is important to state that, in the other study, the investigated outcome was the pain which hindered stevedores from doing their work in the three months prior to the research.

Of all the factors investigated, four were associated with the outcome among temporary dockworkers interviewed, namely: Failure to perform physical activity, doing domestic activities, participating in preschool child care and handling heavy objects.

Sedentariness due to the lack of physical activities outside the work environment was also an observed trend in another study with temporary dockworkers in this city [21]. This gives rise to the supposition that due to the heavy work to which the temporary dockworkers are constantly subjected, it is possible that in their free time there is a trend to do another type of activity which does not involve body movements in order to relax after their working hours.

Male participation in housework either because of men living alone or because of them taking on a role of helping around the house has been more constantly identified [22, 23]. Repeated movements such as washing, ironing, and sweeping, for example, may mean an overload to the effort already done at work by the temporary dockworkers as a result of their handling heavy objects.

In the same way, taking care of preschool children is a task which requires a number of sudden movements, like trunk flexion, and their repetition also contributes to the occurrence of musculoskeletal disorders in workers who already perform activities considered exhausting due to the excess weight which they have to deal with at work. The fourth factor associated with the occurrence of WMSD was handling heavy objects.

The individualized analysis by worker categories showed that the low back was the region most-mentioned as being painful by the capatazia (organizers); a lower level of low back pain prevalence has been found by other authors [24, 25]. Low back pain is a frequent condition in industrialized societies affecting around 70 to 80% of the economically active population, making it one of the main reasons for retirement due to employment disability. It is routinely accompanied by relapses with exacerbation of the painful process and limitation of range of movement [26, 27]. There is evidence that low back pain is related to exposure to some factors causing musculoskeletal injuries, such as the handling of heavy objects and repetitive movements [28], and data from this study corroborates these studies, as an increase of 83% of risk of work-related musculoskeletal disorders was noted among those temporary dockworkers handling heavy objects during their work activity.

Working with stowage was more associated with musculoskeletal discomfort in the shoulder region, similar to other studies which identified 22% of stevedores with work-related muscular pains in the upper extremities [11]. The capatazia (organizers) emphasized the lumbar region (22.5%) as the most painful area. The activities performed by these workers are heavy and demand constant strength. This activity requires good physical conditioning by the temporary dockworkers to prepare the body musculature for the labor intensive routine to which they are subjected daily. In this way pains can be avoided, contributing to the worker’s own performance, bringing them health benefits and work satisfaction, as well as increasing productivity [29].

With regard to quality of life, a positive relationship with the absence of work-related musculoskeletal disorders was noted in the functional capacity scales (89.8) and the vitality scales (84.4). This corroborates Martarello and Benatti’s findings (2009) [25] who both found 96.8 and 80.0 for the same scales, respectively. In their study Martinez and Latorre (2008) [15] also found a high score for functional capacity (91.2), although the score for vitality (72.8) was lower.

Also with regard to quality of life, a significant decrease in the values attributed by the workers who mentioned some work-related muscle pain in all scales was observed, especially physical aspects and pain. This was also found by Martarello and Benatti (2009) [25]. The results of this study showed higher scores on the quality of life scale for temporary dockworkers not reporting musculoskeletal disorders and, consequently, lower scores for those with work-related musculoskeletal symptoms.

A recent study which evaluated the quality of life of maritime tugboat workers in the same city showed that the physical and environmental domains had the highest and lowest scores, respectively. These evaluations did not change significantly after these workers were submitted to a health promotion program based on healthy eating education and periodical physical activity for a period of 22 weeks. The authors suggest that changes in the quality of life of these workers require longer-term interventions which enable positive and gradual changes in habits; mainly due to the intrinsic characteristics of work activities performed such as the stress load, the handling of heavy objects and long working hours [30, 31].

5 Conclusions

This study has shown an association between work-related musculoskeletal disorders and lack of physical activity, carrying out household activities, participation in the care of preschool children and handling heavy objects. Stevedores were those who most reported pain in the shoulders and hips/legs and the capatazia workers reported the low back and shoulders as the most painful sites. Temporary dockworkers who did not report work-related musculoskeletal disorders demonstrated better quality of life.

The data obtained in this study highlighted the importance and urgency of supporting action plans according to the needs of this specific population of workers, especially regarding the reduction of risk factors that may affect musculoskeletal health. In the same way, despite of the peculiarities related to each type of work and its respective cultures, it is perceived a global trend that reports to the high prevalence of WMSD and evidencing the urgent necessity of preventing this disorders in the workplace promoting health [32, 33].

Considering the complexity of the health situation of temporary dockworkers, the limitations of the present work can be seen, suggesting that new analyses need to be made concerning the health complaints of the temporary dockworkers, because only a few variables were considered in this study and it would be necessary a broader approach related to worker’s health. Encouraging the adoption of healthy life habits such as nutritional care and regular physical activities may significantly contribute to an improvement in the quality of life of temporary dockworkers. For this to happen, thought needs to be given to a follow-up program for these workers in the medium and long term.

Conflict of interest

The authors declare that they have no competing interests.

Authors’ Contributions

MPC prepared the initial project (conception and study design), contributed in part of the collection, data analysis and interpretation, and was involved in drafting the manuscript and revising it critically for intellectual content. LGS contributed substantially to this study conception, contributed in part of the collection, and data analysis, and was involved in drafting the manuscript. MCFS contributed substantially to this study conception, it contributed in part of data analysis and interpretation, and was involved in drafting the manuscript and revising it critically for intellectual content. All authors read and approved the final manuscript.

References

Buss

. An introduction to the concept of health promotion. IN: CZERESNIA, Dina FREITAS, Carlos Machado (org.). Health promotion: Concepts, thoughts, trends. Rio de Janeiro: Fiocruz, 2003;15–38.

Walsh

IAP

, Corral

, Franco

, Canetti

EEF

, Alem

MER

, Coury

HJCG

. Work ability of subjects with chronic musculoskeletal disorders. Rev Saúde Públ 2004;38(2):149–156.

International Labor Organization. World Day for Safety and Health at Work 2005. [updated 2013 January 13; cited 2013 February 9] Available from: http://www.oitbrasil.org.br/htsites/safe_day/download/safeday_indicadores.pdf.

International Labor Organization. Working without Risk and Safety Culture - World Day for Safety and Health at Work. 2004. [updated 2013 January 23; cited 2013 February 7] Available from: http://www.oitbrasil.org.br/htsites/safe_day/download/safeday_dados_estatisticos.pdf.

Magri

, Kluthcovsky

ACGC

. Quality of life at work: A review on the scientific production. Rev. Salus-Guarapuava 2007;1(1):87–94.

Lundstrom

, Pugliese

, Bartley

, Cox

, Guither

. Organizational and environmental factors that affect worker health and safety and patient outcomes. Am J Infect Control 2002;30(2):93–106.

Mehta

, Parijat

. Associations between psychosocial risk factors and musculoskeletal disorders: Application to the IT profession in India. Work 2012;41(Suppl 1):2438–2444.

Reinhardt

, Fischer

. Barriers to interventions aimed at promoting the health of health care workers in Brazil. Pan Am J Public Health 2009;25(5):411–417.

Ribeiro

. Repetition Strain Injury (RSI): An emblematic illness. Cad. Saúde Pública 1997;13(supl 2):85–93.

10.

Brandão

, Horta

, Tomasi

. Signs of musculoskeletal disorders in bank workers from the city of Pelotas and region: Prevalence and associated factors. Brazilian Journal of Epidemiology 2005;8(3):295–305.

11.

Cavalcante

FFG

, Gomes

ACN

, Nogueira

FRA

, et al. Occupational risks among dock workers in the Port of Mucuripe, Fortaleza, Brazil. Ciênc. saúde coletiva 2005;10(sup):101–110.

12.

Pinheiro

, Trócolli

, Carvalho

. Validity of the Nordic Musculoskeletal Questionnaire as morbidity measurement tool. Rev. Saúde Públ 2002;36(3):307–312.

13.

Ciconelli

, Ferraz

, Santos

, Meinão

, Quaresma

. Brazilian - Portuguese version of the SF-36. A reliable and valid quality of life outcome measures. Brazilian Journal of Rheumatology 1999;39(3):143–150.

14.

BRAZIL. HEALTH MINISTERY. HEALTH NATIONAL COUNCIL. [updated 2013 January 19; cited 2013 June 16] Resolution 466 of December 12th, 2012. Available from: http://conselho.saude.gov.br/resolucoes//Reso466.pdf.

15.

Martinez

, Latorre

MRDO

. Health and work ability of workers of the electricity sector in São Paulo. Ciênc. saúde coletiva 2008;13(3):1061–1073.

16.

Barberino

, Carvalho

, Silvany-Neto

, et al. Liver changes in workers at an oil refinery and in a reference population in the state of Bahia, Brazil. Pan Am J Public Health 2005;17(1):30–37.

17.

Martinez

, Latorre

MRDO

. Risk Factors for Hypertension and Diabetes Mellitus in Metallurgic and Siderurgic Company’s Workers. Arq Bras Cardiol 2006;87:471–479.

18.

Pöhjonen

. Age-related physical fitness and the predictive values of fitness tests for work ability in home care work. J Occup Environ Med 2001;43:723–730.

19.

Soares

JFS

, Cezar-Vaz

, Mendoza-Sassi

, et al. Temporary workers’ perceptions of occupational risks in the port of Rio Grande, Rio Grande do Sul State, Brazil. Cad. Saúde Pública 2008;24(6):1251–1259.

20.

Garcia

VMD

, Mazzoni

, Corrêa

, Pimenta

. Profile analysis of patients with muscle disease related to work (WMSDs) and service user health worker SUS in Belo Horizonte. Rev Bras Fisioter 2004;8(3):273–278.

21.

Blanco

. Physical activity and health promotion: A study with Temporary Port Workers from Rio Grande/RS harbor. Dissertation presented to Program of Post-Graduation in Nursing of Federal University of Rio Grande/RS 2008, pp. 112.

22.

Assuncão

, Vilela

LVO

. Repetitive Strain Injury - Guide for Health Professionals. Piracicaba-SP: Reference Centre for Occupational Health - CEREST, 1.ed., 2009, p. 168.

23.

Suadicani

, Hansen

, Fenger

, Gyntelberg

. Low back pain in steelplant workers. Occup Med (Lond) 1994;44(4):217–221.

24.

Picoloto

, Silveira

. Prevalence of musculoskeletal symptoms and associated factors among metal industry workers in Canoas-RS. Ciênc. saúde coletiva 2008;13(2):507–516.

25.

Martarello

, Benatti

MCC

. Quality of life and musculoskeletal symptoms in hospital housekeeping workers. Rev Esc Enferm 2009;43(2):422–428.

26.

Andrade

, Araújo

AGR

, Vilar

MJP

. “Back School”: Historical Revision and Its Application in Chronic Low Back Pain. Brazilian Journal of Rheumatology 2005;45(4):224–228.

27.

Tsukimoto

, Ribeiro

, Brito

, Battistella

. Longitudinal evaluation of Posture School for low back pain by the questionnaires Rolland Morris and Short Form Health Survey (SF-36). Acta Fisiatr 2006;13(2):63–69.

28.

Punnett

, Wegman

. Work-related musculoskeletal disorders: The epidemiologic evidence and the debate. Journal of Electromyography and Kinesiology 2004;14:13–23.

29.

Cromie

, Robertson

, Best

. Work-Related Musculoskeletal Disorders and the Culture of Physical Therapy. Physical Therapy 2002;82(5):459–472.

30.

Baena

, Rocha

CLL

, Franco

, et al. Health profile of seafarer workers that will take part in a health promotion program. Vittalle –Journal of Health Sciences 2010;22(1):65–74.

31.

Baena

, Muccillo-Baisch

, Almeida

, et al. The impact of a pilot project on health promotion for maritime tugboat workers. Rev. bras. saúde ocup 2011;36(124):288–296.

32.

Akter

, Maruf

, Chowdhury

. Prevalence of musculoskeletal symptoms and associated factors: A cross-sectional study of metal workers in Bangladesh. Work 2015;50:363–370.

33.

Hunter

, Silverstein

. Perceptions of risk from workers in high risk industries with work related musculoskeletal disorders. Work 2014;49:689–703.