From The Ergoweb® Learning Center

Potential Physiological Mechanism Identified for Psychosocial Risk Factor-induced Musculoskeletal Pain

A Swiss study involving 32 public service workers showed that higher workday rates of norepinephrine excretion occurred among volunteers with high musculoskeletal pain compared to rates of norepinephrine excretion among low musculoskeletal pain subjects.  This suggests that jobs with high psychosocial risk factors promote activation of the sympathetic-adrenal medullary system, resulting in a higher secretion of norepinephrine – a hormone and neurotransmitter which increases muscle activity.

Further, the research found an association between musculoskeletal pain and trained observer-identified psychosocial risk factors. 

The Bottom Line – How This Applies To Ergonomists
Most ergonomists concentrate on physical risk factors when analyzing a job.  By demonstrating an association between psychosocial risk factors, musculoskeletal pain, and a physiological mechanism that can contribute to musculoskeletal symptoms, this research:
• revealed how psychosocial risk factors may contribute to orthopedic disorders
• indicated the value of assessing psychosocial risk factors

Also, this study was unique in that psychosocial factors were determined by trained observers instead of using the subjective opinion of study volunteers.  

Other Significant Findings
1) Subjects with high musculoskeletal pain also had higher levels of job control.
2) The prevalence of daily low back, neck, and shoulder pain was 6.2 percent, 3.1 percent, and 6.2 percent respectively.
3) Less than 16 percent reported never having experienced low back pain over the prior year.
4) Approximately half of the study’s subjects were considered to have a low frequency of musculoskeletal pain.

Study Design
From a public service organization, 32 healthy, full-time working males were recruited as study volunteers.

Work and Home Environment Evaluation
Trained evaluators rated the subjects’ work activities for intensity/frequency of work stressors and job control.

In the home setting, the domestic activity and its duration (i.e., household chores, child care, or caring for relatives) were reported at 9:00 pm.  On Sundays, heavy physical work and demanding mental activity were avoided.

Musculoskeletal Pain Evaluation
Subjects reported the frequency of neck, shoulder, and low back pain that had been experienced over the prior 12 months.

Catecholamine Measurement
Urinary samples were obtained at noon, 3:00 pm, and 9:00 pm by trained collectors on three workdays and three Sundays over a three week period (up to 18 total urinary samples). After a time lag of 6 weeks, the data collection process was repeated for each volunteer. 

The subjects also kept track of intake of alcohol, nicotine, caffeine and medications.

The authors controlled for age, smoking habits, and body weight.

Article Title: Workplace observation of work stressors, catecholamines and musculoskeletal pain among male employees

Publication: Scandinavian Journal of Work, Environment & Health, 34(5), 337-344, 2008

Authors: A Elfering, S Grebner, H Gerber, and N K Semmer

This article originally appeared in The Ergonomics Report™ on 2009-01-14.