Published in the SA Profile Publication December 2017

Dr Busisiwe Nyantumbu-Mkhize DOH, MSc (Med), PhD. Senior Medical Scientist in Ergonomics
Dr Spo Kgalamono DOH, FCPHM (Occ Med), MMed. Occupational Medicine Specialist

Musculoskeletal disorders (MSDs) are painful and disabling conditions.  They encompass a wide range of inflammatory and degenerative conditions affecting muscles, tendons, joints, nerves and blood vessels.  These disorders have been reported in many occupational groups across different industries, worldwide.  They are a major cause of morbidity and disability in working populations and result in substantial economic and social impact.

The body parts that are usually affected are the neck, upper limbs and low back.  Examples of these disorders are rotator cuff syndrome (a condition that affects the shoulders) and low back pain.  The pain is often the main reason for these workers to take time off from work and consult healthcare providers.  This increases sick leave which can adversely affect productivity at work. In addition,  healthcare utilization can increase usage of healthcare resources which has cost  implications.  To add to this burden, a proportion of MSD cases progress to disability and work incapacity.  For instance, they may find it difficult to do certain tasks at home and at work.  Consequently, these workers may become candidates for early retirement, further eroding public resources and becoming dependent on the state for health care.

MSDs have multiple causation.  This means that they may be caused by factors at work and  outside of work. For this reason, the World Health Organization has classified MSDs as work-related rather than occupational conditions. In work-related conditions, the work environment and the performance of work is said to contribute significantly in their development while occupational conditions are entirely caused by work.  Research studies from many countries, have established a link between the development of MSDs and work.  Physical and psychosocial aspects of work, referred to as ergonomic risk factors, have been identified as the main contributing factors to the development of MSDs.

Risk factors arise from poorly designed workplaces in which ergonomics had not been considered.  Ergonomics aims to match the physical and psychological capabilities of workers with job demands.  A mismatch in this relationship may lead to the development of MSDs. For instance, workers may be at high risk of developing these disorders if their tasks are designed in such a way that they handle heavy loads; the layout of their workstations force them to assume awkward body postures when working; the tools they are using emit vibration; and the demands of their jobs is higher in relation to the control they have in carrying those jobs out.  In these scenarios, the risk may be compounded by the length of time they are exposed to each one of these factors.

In keeping with the objectives of occupational health, South Africa has occupational health legislation: Occupational health and safety act of 1993 which governs the non-mining sector. This Act makes provision for a work environment that is without risks to the health of workers.  Workers are empowered to recognize risks in their jobs making them conversant to these risks.  Following occupational health principles and practice which Ergonomics is an integral part of, the Act provides for occupational health surveillance which includes the work environment and workers’ health.  Work environment surveillance entails the identification, assessment, prevention, monitoring and evaluation of risks while health surveillance aims to apply preventive strategies after the workers had developed the condition of interest but are at an early stage when the condition is still reversible.

The Occupational Medicine Section of the National Institute for Occupational Health has an Occupational Medicine (OM) Clinic where workers suspected of having work-related conditions such as MSDs including Hand-arm Vibration Syndrome (a condition caused by exposure to vibration emitted by hand-held vibrating tools) are referred for clinical evaluation and work-relatedness of MSDs.  Work-relatedness is determined by conducting an ergonomic risk assessment to identify risk factors that the worker is exposed to.  For OM Clinic bookings: Sr Buffel and Mr Senamolela can be contacted at (011) 712 6420 or email address: goitsimangb@nioh.ac.za  and (011) 712 6462  or email address: jacobse@nioh.ac.za, respectively.

Bibliography

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Bernard, B. P. 1997. Musculoskeletal disorders and workplace factors: a critical review of epidemiologic evidence for work-related musculoskeletal disorders of the neck, upper extremity, and low back. NIOSH.

Buckle, P. W. &  Devereux, J. 2002. The nature of work-related neck and upper limb musculoskeletal disorders. Applied Ergonomics, 33, 207-217.

World Health Organization 1985.  Identification and control of work-related diseases.  Geneva, Switzerland:  WHO.  WHO Technical Report Series 714.

Department of Labour, South Africa. 2005.  Occupational Health and Safety Act and Regulations.  Revised fourth edition, LexisNexis, Butterworth.

Punnett, L. & Wegman, D. H. 2004. Work-related musculoskeletal disorders: the epidemiologic evidence and the debate. Journal of Electromyography and Kinesiology, 14, 13-23.