The impact of ergonomics intervention on psychosocial factors and musculoskeletal symptoms among office workers

Abstract

Musculoskeletal disorders have a multi factorial etiology that includes not only physical risk factors but also psychosocial factors. This study aimed to investigate psychosocial risk factors and musculoskeletal symptoms among office workers of an Iranian oil refinery and also to examine the subsequent effects of ergonomics intervention on musculoskeletal discomfort and psychosocial risk factors.

In this study, 73 office workers as a case group and 61 office workers as a control group from an Iranian oil refinery plant were randomly selected and examined. The Nordic Musculoskeletal Disorders Questionnaire and the Persian version of the Job Content Questionnaire (P-JCQ) were used as collecting data tools before and after the interventional program.

Low back problem (28.8%) was found to be the most common problem among the office workers. Significant differences found between prevalence rates of reported musculoskeletal in upper back, lower back and feet/ankle regions before and after intervention. Our findings showed that psychosocial variables were not affected by the intervention. The only variables on the P-JCQ that were significantly different pre/post intervention are the physical variables: physical job demands, physical exertion and physical isometric load. None of the other psychosocial variables were found to be significant. With the top management support, improvements in all office workstation components were made successfully.

Relevance to industry

Recently, changes in the nature of work draw increased attention to the relation between psychosocial factors and musculoskeletal disorders. The results of the current study indicate that a well conducted implementation of an interventional program can lead to a decrease in musculoskeletal symptoms and to some extent in the psychosocial factors at work.

Introduction

Recently, many studies have shown that musculoskeletal disorders (MSDs) are related to physical and psychological perceived job demands in the work environment (Fredriksson et al., 2001, Choobineh et al., 2006, Choobineh et al., 2009, Lee et al., 2008, Lapointe et al., 2009, Lin et al., 2009, Warming et al., 2009, Canjuga et al., 2010, Fernandes et al., 2010, Johnston et al., 2010, De Souza Magnago et al., 2010, Dawson et al., 2011, Driessen et al., 2011, Gilbert-Ouimet et al., 2011, Haukka et al., 2011, Vandergrift et al., 2011, Westgaard and Winkel, 2011). The economic loss due to such disorders affects not only the individual but also the organization and the society as a whole (Kemmlert, 1994). Musculoskeletal disorders have followed working days lost, disability of workers (Shahnavaz, 1987, Genaidy et al., 1993, Tsauo et al., 2009) and wasting money (Neumann, 2004, Punnet and Wegman, 2004, Eashw, 2008). Risk factors of WMSDs are known to include work place activities such as heavy load lifting, repetitive tasks and awkward working postures (Bernard, 1997, Haynes and Williams, 2008), while demographic characteristics and psychosocial factors are also known to be important predictive variables (Linton and Kamwendo, 1989, Weiser, 1997, d’Errico et al., 2010).

The predictors for the risk of developing MSDs can be divided into individual (Ekman et al., 2000, Spyropoulos et al., 2007, Johnston et al., 2008), ergonomic (Demure et al., 2000, Palmer et al., 2001, Nakazawa et al., 2002, Ortiz-Hernandez et al., 2003, Ye et al., 2007, Klussmann et al., 2008, Motamedzade et al., 2011), and psychosocial factors (Faucett and Rempel, 1994, Polanyi et al., 1997, Haufler et al., 2000, Hanse, 2002). In office workers, risk of developing MSDs is higher among workers who have a high work strain, continuous mouse and keyboard use, high muscle tension, and previous MSDs in the neck and shoulder(Kryger et al., 2003, Brandt et al., 2004, Juul-Kristensen et al., 2004, Nicholas et al., 2005, Werner et al., 2005, Hush et al., 2009).

Workers with musculoskeletal problems are usually recommended to change work methods, use load carrying equipment etc., but interventional studies have shown that these recommendations have little effect on reducing the prevalence of musculoskeletal symptoms (Torp et al., 1999). Ergonomic interventions are expressed as a means to improve working conditions (Motamedzade et al., 2003). There is evidence that ergonomic interventions are not solely sufficient to control musculoskeletal disorders, but psychosocial conditions should also be considered. Burton et al. (1997) found that workers with back pain had more negative psychological perception about their jobs as compared with those without back problem. This shows the importance of psychosocial issues in work environment.

Ergonomic process is as an appropriate tool to show the relationship between psychosocial risk factors and musculoskeletal disorders (Harcombe et al., 2010).

Methods of educational intervention range from passive techniques to performance-based techniques. Lectures are commonly used to present health- and safety-related information. Other passive techniques include videos and pamphlets (Burke et al., 2006). Active approaches to learning are superior to less active approaches. Therefore, as training moves from passive methods to the engaging methods, more transfer of training to the work setting will occur (Burke et al., 2006).

In office working environments, ergonomics training is the best initial strategy to educate computer users about office ergonomics (Westgaard and Winkel, 1997, Ketola et al., 2002, Mahmud et al., 2011). Marcoux et al. (2000) used a range of educational interventions, including posters, emails, pictures of stretching and stress relief activities, workshops, and informational booklets. These interventions increased the workers’ knowledge of MSDs and resulted in changes in the hand/wrist and neck/shoulder posture when using computers. Lewis et al. (2001) conducted a study in a petrochemical facility and reported improvements in workstation posture and symptom severity, but they did not report any reduction in symptoms. Studies using different methods of ergonomics training have reported positive results. For example, those who received education programs, such as participatory training and traditional training (lectures and handouts), reported less pain/discomfort and a positive perception of psychosocial work stress compared with those who did not receive training (Bohr, 2002). Recent studies on office ergonomics by Robertson et al., 2008, Robertson et al., 2009) also found positive results.

During recent years several studies have been conducted on the impact of ergonomic interventions on psychosocial factors in the work place (Kerr et al., 2001, Buckle and Devereux, 2002, Aarås et al., 2005, Dainoff et al., 2005, Konarska et al., 2005, Laing et al., 2007, Haukka et al., 2010). Laing et al. (2007) expressed that ergonomic interventions have been improved psychosocial conditions in different working groups. The findings of Haukka et al. (2010) do not support the usefulness of participatory ergonomics intervention in changing unsatisfactory psychosocial working conditions.

In the light of foregoing, this study was conducted with the following objectives: a) to study psychosocial risk factors and musculoskeletal symptoms among office workers of an Iranian oil refinery and b) to investigate the subsequent effects of ergonomics intervention on musculoskeletal discomfort and psychosocial risk factors.