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

The impact of ergonomics intervention on psychosocial factors and musculoskeletal symptoms among office workersContents lists available
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The impact of ergonomics intervention on psychosocial factors and musculoskeletal symptoms among office workers
Alireza Choobineh a, Majid Motamedzade b,*, Maryam Kazemi c, Abbas Moghimbeigi d, Ahmad Heidari Pahlavian e
aResearch Center for Health Sciences, Shiraz University of Medical Sciences, Shiraz, Iran b Ergonomics Department, School of Public Health and Research centre for Health Sciences, Hamedan University of Medical Sciences, Hamedan, Iran c Ergonomics Department, School of Public Health, Hamedan University of Medical Sciences, Iran d School of Public Health and, Research Institute of behavioral Disorder and Substance Abuse, Hamedan University of Medical Sciences, Iran eDepartment of Psychiatry, Medical School, Hamedan University of Medical Sciences, Iran
a r t i c l e i n f o
Article history: Received 27 December 2010 Received in revised form 6 August 2011 Accepted 14 August 2011 Available online 1 September 2011
Keywords: Musculoskeletal disorders Physical job demands Psychological perceived job Office workers
* Corresponding author. Tel.: þ98 811 8255301; fax E-mail addresses: [email protected] (A.Choobin
(M. Motamedzade), [email protected] (A. Moghimbe ac.ir (A. Heidari Pahlavian).
0169-8141/$ e see front matter 2011 Elsevier B.V. doi:10.1016/j.ergon.2011.08.007
a b s t r a c t
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 Ques- tionnaire 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 vari- ables 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 muscu- loskeletal symptoms and to some extent in the psychosocial factors at work.
2011 Elsevier B.V. All rights reserved.
1. 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, 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;
: þ98 811 8255963. eh),[email protected] igi), heidaripahlavian@umsha.
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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 indi- vidual 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).
A. Choobineh et al. / International Journal of Industrial Ergonomics 41 (2011) 671e676672
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 recom- mended to changeworkmethods, use load carrying equipment etc., but interventional studies have shown that these recommenda- tions have little effect on reducing the prevalence of musculoskel- etal 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 rela- tionship between psychosocial risk factors and musculoskeletal disorders (Harcombe et al., 2010).
Methods of educational intervention range from passive tech- niques 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 engagingmethods, more transfer of training to thework 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 inter- ventions, 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 inworkstation posture and symptom severity, but they did not report any reduc- tion 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, 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 ergo- nomics 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.
2. Material and methods
This interventional study (quasi-experimental) was conducted from March 2010 to October 2010. The study population, were full- time office workers employed at an Iranian oil refinery plant. Totally, 73 employees as a case group and 61 employees as a control group were randomly selected and examined. The two groups were studied before and after the intervention. The data were gathered using anonymous questionnaire which was consisted of three parts and covered the following items: personal details (including gender, age, weight, height, body mass index (BMI), job tenure, daily working time (hrs), marital status, education, health and medical background); musculoskeletal problems in different body regions; and perceived job demands. They assigned their own anonymous identification numbers to the questionnaires for future tracking. Reported musculoskeletal symptoms were limited to the past 6 months. Each participant received the questionnaire in person in her/his work place.
The Persian version of general Nordic Questionnaire of muscu- loskeletal symptoms was used to examine reported cases of MSDs among the study population (Kuorinka et al., 1987). The Job Content Questionnaire (JCQ) was used to measure perceived job demands (Karasek, 1985). The JCQ contains items of work demands including both physical and psychological aspects. It has been used to study the relationship between work demands and work-related outcomes (i.e., MSDs, cardiovascular disease, etc.) in different countries (Karasek et al., 1998). Items were in Persian language and their linguistic validity had been assessed through forward and backward translation methodology. Reliability and validity of the Persian version of JCQ (P-JCQ) were explored in a separate study showing satisfactory psychometric properties of the questionnaire (Choobineh et al., 2011). In this study, 39 items in 5 scales were totally included in the P-JCQ as follows:
- Decision latitude (9 items) - Psychological job demands (9 items) - Physical job demands including physical exertion and physical isometric load (5 items)
- Occupational physical hazards (8 items) - Social support (8 items)
Each item was scored based on a four-point scale (i.e., strongly agree to strongly disagree or often to never). For all items their middle points were compared as a basis and rates were calculated on more and less than the value of median.
Educational intervention took place including 4 appropriate 1-h training sessions, providingworkers with educational pamphlets to being familiar with the ergonomics principles and its objectives, disorders and ergonomic work place conditions. After awareness, the workers encouraged to stay at their workstation so that the trainer could help them readjust their workstation if necessary. The trainer made suggestions on how to improveworkstation practices. Workers were also encouraged to participate in their workstation adjustments. Under some circumstances, further suggestions were made on how to adjust the workstation and/or space.
After completion of ergonomics training, employees became skilled at how to analyze and evaluate the work environment and suggestions for improvement were developed and presented. The
Table 1 Demographic characteristics of employees studied.
Variables Case group (n ¼ 73)
Control group (n ¼ 61)
P- value
Age (yrs) (Mean SD) 36.4 17.88 35.28 6.77 .332 Job tenure (yrs)
(Mean SD) 8.76 7.8 7.84 5.55 0.178
BMI (Mean SD) 26.37 15.07 24.4 2.6 0.143 Gender Female 57 (%78.1) 48(%78.7) 0.933 Male 16 (%21.9) 13 (%21.3)
Marital status Single 5 (%6.8) 9 (%14.8) 0.151 Married 68 (%93.2) 52 (%85.2)
Education Diploma 16 (%21.9) 11 (%18) Associate Degree 6 (%8.2) 15 (%24.6) 0.193 BSc 37 (%50.7) 29 (%47.5) MSc 14 (%19.2) 6 (%9.8)
Table 2a Prevalence rate of reported MSDs in different body regions of case subjects before and after intervention (n ¼ 73).
Body regions Before intervention After intervention P-valuea
Yes (%) No (%) Yes (%) No (%)
Neck 18 (24.7) 55 (75.3) 13 (17.8) 60 (82.2) 0.063 Shoulders 12 (16.4) 61 (83.6) 11 (15.1) 62 (84.9) 1.000 Elbows 5 (6.8) 68 (93.2) 5 (6.8%) 68 (93.2) 1.000 Wrist/hands 9 (12.3) 64 (87.7) 7 (9.5) 66 (89.5) 0.625 Upper back 12 (16.4) 61 (83.6) 2 (2.7) 71 (97.3) 0.002 Lower back 21 (28.8) 52 (71.2) 5 (6.8%) 68 (93.2) 0.000 Thighs 10 (13.7) 63 (86.3) 5 (6.8%) 68 (93.2) 0.063 Knees 16 (21.9) 57 (78.1) 14 (19.2) 59 (80.8) 0.625 Feet/ankles 15 (20.5) 58 (79.5) 3 (4.1) 70 (95.9) 0.000
a McNemar analysis.
Table 2b Prevalence rate of reported MSDs in different body regions of control subjects before and after intervention (n ¼ 61).
Body regions Before intervention After intervention P-valuea
Yes (%) No (%) Yes (%) No (%)
Neck 9(15.5) 49(84.5) 4(6.9) 54(93.1) 0.180 Shoulders 6(10.3) 52(89.7) 3(5.2) 55(94.8) 0.375 Elbows 1(1.7) 57(98.3) 2(3.4) 56(96.6) 1.000 Wrist/hands 9(15.5) 49(84.5) 4(6.9) 54(93.1) 0.065 Upper back 8(13.8) 50(86.2) 3(5.2) 55(94.8) 1.000 Lower back 4(6.9) 54(93.1) 6(10.3) 52(89.7) 0.625 Thighs 5(8.6) 53(91.4) 5(8.6) 53(91.4) 1.000 Knees 10(17.2) 48(82.8) 9(15.5) 49(84.5) 1.000 Feet/ankles 4(6.9) 54(93.1) 3(5.2) 55(94.8) 1.000
a McNemar analysis.
A. Choobineh et al. / International Journal of Industrial Ergonomics 41 (2011) 671e676 673
outcomes assessed at the 6 month after training. Workers were asked if they had experienced any MSDs at any time during the previous 6 months.
Statistical analyses were performed using SPSS (version 13). McNemar test was used to compare the groups before and after intervention in term of musculoskeletal symptoms. To compare P- JCQ scores before and after intervention, paired t-test was applied. Chi-square tests were used to assess associations between perceived variables and reported musculoskeletal symptoms.
3. Results
Table 1 presents means and standard deviations of age, job tenure and BMI as well as gender, marital status and educational level of the participants in both case (n ¼ 73) and control groups (n ¼ 61). As seen, the two groups were similar in term of demo- graphic variables and no differences were found between case and control individuals.
Regarding improvements of the poor conditions, with the top management support, the overall performance was considerable. Some of the most important examples include:
1 Purchase of foot rests, 2 Improvement of some used chairs, 3 Purchase of ergonomic chairs for many workstations, 4 Individual height adjustment for both the keyboard and monitor.
5 Individual adjustment of the chair 6 Individual adjustment of the pointer/mouse 7 Providing wrist/palm supports for office workers 8 Individual adjustment of the telephone depending on usage patterns.
Table 2a depicts musculoskeletal symptoms in the case subjects before and after intervention. McNemar test indicated significant differences between prevalence rates of reported musculoskeletal in upper back (P ¼ 0.002), lower back (P ¼ 0.000) and feet/ankle (P ¼ 0.000) regions before and after intervention. The prevalence rates of problems were significantly lower after intervention.
Table 2b depicts musculoskeletal symptoms in the control subjects before and after intervention. McNemar test indicated no significant differences between prevalence rates of reported musculoskeletal in all regions before and after intervention.
Table 3a demonstrated means and standard deviations of scores of different scales of Persian version of the job content question- naire (i.e., decision latitude, psychological job demands, physical
job demands, social support and physical hazard) in the case individuals before and after the intervention. The only variables on the P-JCQ that were significantly different pre/post intervention were the physical variables. Paired t-test revealed that there were significant differences between before and after intervention means of scores in physical exertion (P ¼ 0.043), physical isometric load (P ¼ 0.000) and physical job demands (P ¼ 0.000). None of the other psychosocial variables were found to be significant.
According to Table 3b, no significant difference was noted in each of the scales of Persian version of the job content question- naire before and after intervention in control group. No significant relationship was found between prevalence rates of reported musculoskeletal problems in different body regions and psycho- social scales before and after the intervention. In this analysis, using Chi-square test, the middle maximum of each psychosocial scale was based.
4. Discussion
In this study, 73 employees including 16 female and 57 male workers of an Iranian refinery plant were examined as the case subjects. The results revealed that prevalence rate of the reported symptoms in upper back, lower back and feet/ankles regions reduced significantly after the intervention. This shows that inter- ventional programs have been effective in symptoms reduction of the mentioned regions. No change was observed before and after intervention in the control individuals. Our finding is in agreement with the findings of other studies that reported reductions in MSDs among computer users after attending training (Laing et al., 2007; Robertson et al., 2008, 2009; Mahmud et al., 2011). In Laing study (2007) conducted in a Canadian automobile factory, after 11 months of an interventional program reduction of back and foot symptoms were observed.
Table 3a Means and standard deviations of scores of different scales of Persian version of the job content questionnaire in the case subjects before and after the intervention (n ¼ 73).
Scales of P-JCQ Mean before intervention Mean after intervention Mean difference Standard deviation t P-valuea
Decision latitude (n ¼ 9)c 67.2123 64.8754 0.9321 8.21321 5.943 0.089 Psychological job demands (n ¼ 9)c 9.5231 9.5385 0.04164 2.00308 0.177 0.860 Physical exertion (n ¼ 3)c 8.9385 8.6615 0.29167 1.20372 2.056 0.043 Physical isometric load (n ¼ 2)c 5.2154 4.8769 0.76389 1.20437 5.382 0.000 Physical job demandsb (n ¼ 5)c 14.1538 13.5385 1.05556 2.02024 4.433 0.000 Physical Hazard (n ¼ 8)c 17.4462 16.8308 0.55556 3.19722 1.474 0.145 Social support (n ¼ 8)c 25.2000 25.4308 0.18056 2.54717 0.601 0.549
a Paired t-test. b Combination of the physical exertion and the physical isometric load scales. c Number of items.
Table 3b Means and standard deviations of scores of different scales of Persian version of the job content questionnaire in the control individuals before and after the intervention (n ¼ 61).
Scales of P-JCQ Mean before intervention Mean after intervention Mean difference Standard deviation t P-valuea
Decision latitude (n ¼ 9)c 64.7731 64.5225 0.14321 7.10869 2.577 0.402 Psychological job demands (n ¼ 9)c 9.9483 10.0690 0.12069 2.22488 0.413 0.681 Physical exertion (n ¼ 3)c 7.2586 7.6310 0.37241 2.19559 2.332 0.223 Physical isometric load (n ¼ 2)c 4.5172 4.9483 0.43103 1.39060 2.361 0.322 Physical job demandsb (n ¼ 5)c 11.7759 11.8793 0.80345 3.41662 2.460 0.317 Physical Hazard (n ¼ 8)c 13.1897 13.9310 0.74138 4.60191 2.882 0.536 Social support (n ¼ 8)c 25.3793 25.1724 0.20690 2.06694 0.762 0.449
a Paired t-test. b Combination of the physical exertion and the physical isometric load scales. c Number of items.
A. Choobineh et al. / International Journal of Industrial Ergonomics 41 (2011) 671e676674
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. The mean score of physical job demands scale was improved after intervention indicating effectiveness of imple- mentation of the interventional programs in physical risk factor exposure reduction (i.e., elimination or minimization of lifting heavy loads and awkward working postures). This could be attributable to improved workers’ awareness of physical risk factors, resulting in decreased job stress, and also better commu- nication among workers because of the reduction in stress and job physical load. These results are expected given the kinds of inter- ventions that were put in place.
No significant relationship was found between prevalence rate of musculoskeletal symptoms and psychosocial factors in the case group before and after the intervention. It is in line with the results of a study by Choobineh et al. (2006) conducted on nurses inwhich no association was found between psychological factor and musculoskeletal problems. Regarding this, Kerr et al. (2001) pointed out that when physical demands were included in a model of musculoskeletal…