Work-Related Neck Pain in Female Office Workers: A Psychosocial and Physiological Profile

Work-related musculoskeletal disorders comprise a significant proportion of workplace injuries in the western industrialized society and a burden on our workers compensation system. In particular, work with computers is associated with an increased risk for neck pain which is more prevalent in women. To provide effective prevention and management programs, a better understanding of the processes underlying these disorders is necessary. This research aimed to obtain a profile of the psychosocial and physiological characteristics of female office workers with self-reported neck pain and disability. The first aim was to identify factors within the workplace (psychosocial and ergonomic) associated with a greater risk of neck pain in a sample of female office workers. The second aim was to map the relationship between quantitative sensory measures and neck pain in a subset of these workers. Finally, a study of cervical musculoskeletal function was undertaken using recordings of the myoelectric activity of the superficial cervical flexors and extensors during functional and non-functional tasks. The neck disability index (NDI) was the outcome measure for all studies. Study 1: Risk factors within the workplace were identified using a comprehensive self-report survey distributed to organizations employing female office workers. The interaction between the three main psychosocial domains was investigated after controlling for individual and ergonomic risk factors. It was found that as job demands increased, high decision authority had an increasing effect on the level of neck pain and disability when supervisor support was low. Study 2: Individual and ergonomic factors within the work environment associated with the presence and the severity of neck pain in the female office worker are reported in this study. Higher NDI scores were associated with: using the computer mouse longer than six hours per day, greater negative affectivity (an inherent personality trait), older age and an uncomfortable workstation. Most workstation features were not significantly associated with NDI scores. Factors associated with neck pain were: a history of neck trauma, wearing vision correction with graduated lenses and greater negative affectivity. The results suggest a combination of individual and task demands need to be evaluated to better target workplace prevention and intervention campaigns. Johnston, V., Jimmieson, N.L., Souvlis, T., Jull, G. Risk factors for neck pain and disability in female office workers. Poster, 16th World Congress on Ergonomics, July 2006, Maastricht, The Netherlands. Johnston, V., Relationship between the various risk factors for work-related neck pain in female office workers. Oral Presentation, 26th Annual Scientific Meeting of the Australian Pain Society, April 2006, Melbourne. Johnston, V., Jimmieson, N.L., Souvlis, T., Jull, G. Work related neck pain: an investigation of the relationship between the physical and psychosocial features in the female office worker. Oral Presentation, Musculoskeletal Physiotherapy Australia Conference, November, 2005, Brisbane. Johnston, V., Souvlis, T., Jull, G. Jimmieson, N.L. A profile of work-related neck pain in female office workers. Oral Presentation, Post-graduate Research Day, School of Health and Rehabilitation Sciences, The University of Queensland. December, 2003. Grants Awarded Dorothy Hopkins Award, Queensland Branch of the Australian Physiotherapy Association, $500 Physiotherapy Research Foundation, Australian Physiotherapy Association, $1250. Additional Publications by the Candidate Relevant to the Thesis but not Forming Part of it Johnston, V. (2006). Biological pathways between occupational stress and work-related musculoskeletal disorders of the neck and upper extremity. Submitted to Physical Therapy Reviews student review competition in September, 2006 and awarded the prize for the best student review. Accepted for publication February, 2007. Additional Publications by the Candidate Not Relevant to the Thesis Souvlis, T., Johnston, V. (2004). Pain in the elderly. In J. C. Nitz and R. R. Hourigan (Eds.), Physiotherapy Practice in Residential Aged Care (pp. 307-331). London: Butterworth- Heinemann. The next three papers report on the sensory and motor changes associated with neck pain in a sub-set of the office workers who participated in the survey. Volunteers who met the inclusion criteria (n=85) were categorized according to their scores on the NDI: no pain (33, NDI;&lt8); mild pain (38, NDI 9-29); moderate pain (14, NDI;&gt30). A fourth group of non-working women without neck pain (n=22) formed the control group. Study 3: The relationship between sensory features and participant group was explored using quantitative sensory testing. The results showed a moderate dose-response relationship between pain level and sensory measures with significant multi-modal changes in response to temperature, pressure pain threshold and vibration stimuli. These findings provide evidence of widespread sensitivity most likely due to altered central nociceptive processing initiated and sustained by peripheral nociceptive input. Study 4: Physical impairments in motion and cervical muscle function were explored using surface electromyography to record myoelectric activity of the cervical flexor muscles during cranio-cervical flexion, and of the cervical flexor and extensor muscles during a unilateral arm task. Workers with neck pain demonstrated reduced rotation movement and altered muscle recruitment strategies consistent with other cervical musculoskeletal disorders. Study 5: The myoelectric activity of the cervical flexor and extensor muscles during and after five minutes of copy-typing, typing with stress and stress only tasks was recorded. Workers (with and without neck pain) demonstrated higher activity than controls in the cervical flexor and extensor muscles in response to these tasks which was not observed in the upper trapezii. This suggests that stress may not be a primary reason for these findings but rather they represent altered cervical muscle recruitment related to a musculoskeletal disorder. Study 6: The contribution of all factors associated with neck pain in female office workers was explored using regression modelling. Variables differentiating workers with and without pain were: using the computer mouse longer than six hours per day, higher negative affectivity scores, cold hyperalgesia, reduced neck rotation, longer duration of symptoms and higher activity in the cervical flexors during cranio-cervical flexion. These findings suggest that a combination of work practices, an inherent psychological state, altered pain processing and altered muscle function can identify workers with greater neck pain. The results of this thesis represent a significant contribution to understanding the pathophysiological processes associated with neck pain in female office workers. There are global deficits in the processing of pain and motor control strategies utilized during functional and stressful tasks. In the presence of prolonged computer mouse use, and augmented by the psychological state of negative affectivity, these deficits have a negative impact on health and well-being of office workers. Management of neck pain in office workers requires a multidisciplinary approach to address the many factors associated with neck pain and disability