Study: Psychosocial Factors Significantly Related to Shoulder Pain

[Editore's note: This article is reprinted, with permission, from The Ergonomics Report™, Ergoweb's popular subscription-based online publication. Subscribers have had access to this article since July 6, 2010.]

Hotel room cleaners who reported a high work effort yet a low work reward (e.g., job salary, self-esteem, and opportunities) – called an Effort Reward Imbalance – were three times as likely to experience severe/very severe shoulder pain according to a University of California Berkeley study involving 493 Las Vegas hotel room cleaner subjects.  Lower social support and total social support were also associated with severe/very severe shoulder pain (the outcome of interest).

The incidence/severity of shoulder pain within the prior 4 weeks was reported by hotel room cleaners as:

• None – 8%
• Very mild – 5%
• Mild – 10%
• Moderate – 22%
• Severe – 27%
• Very severe – 29%

After controlling for physical workload, there was no significant association between shoulder pain and job strain/iso-strain (e.g., psychological demands, decision latitude, coworker support, and supervisor support).

Similar to other studies, this research found an association between shoulder pain and higher physical workload, greater work intensity compared to five years ago, and higher number of ergonomic concerns.

The Bottom Line – How This Applies To Ergonomists
Ergonomists are quick to identify and address physical risk factors when performing their work.  If an analysis overlooks psychosocial/organizational factors, the assessment may be short sighted. 

This study showed that, when controlling for physical work demands, a very strong relationship was seen between severe/very severe shoulder pain and psychosocial risk factors as measured through the Effort Reward Imbalance. 

The authors suggest potential methods that may control an Effort Reward Imbalance include recognition of the importance of mutual respect and having a reward system that appropriately recognizes employee effort.

This study also supports the concept that ergonomists can play a significant role in organizational/management design, since psychosocial concerns are often driven by management systems and methods. (Interested readers should also see OSHA, Unions and Ergonomics in the Hospitality Industry for more on this topic)

Other Key Points
There was a significantly higher prevalence of shoulder pain among workers who were married/partnered, of Latina ethnicity, possessed fewer years of education, had shorter height, and were born outside the United States.

Smoking and alcohol use had no correlation with severe/very severe shoulder pain.  

Citing other investigations, the authors note the physiologic mechanisms by which psychosocial work factors may influence the onset of a musculoskeletal disorder could involve stimulation of the adrenal-cortical stress response, which could lead to:

• Changed work patterns
• Assumption of poor work postures
• Altered perceptions/response to pain

In 2006, the Bureau of Labor Statistics ranked maids and housekeepers as 13th in the number of total cases of work-related musculoskeletal disorders with an incidence rate of 90.5 cases/10,000 full-time workers (average national incidence rate was 38.6 cases/10,000 full-time workers).

Research Method
The 2002 Hotel Room Cleaner Study provided the data for this analysis.  Room cleaners from five different types of Las Vegas unionized casino hotels participated in the study.  Out of 1,276 potential subjects, 493 completed all the research questionnaire information which was collected via interviews with trained researchers after work.

Data collected included:

• Location and degree of shoulder musculoskeletal pain over the prior 4 weeks
• Job Strain and Iso-strain (measured through psychological demands, decision latitude, coworker support, and supervisor support).
• Effort Reward Imbalance (an evaluation of the worker’s self-perceived work effort compared to job salary, self-esteem, and opportunities)

Controls were established for biomechanical, socio-demographic, behavioral and anthropometric factors.

Access
This study can be acquired at: http://www3.interscience.wiley.com/journal/123329671/abstract

Article Title: Psychosocial Work Factors and Shoulder Pain in Hotel Room Cleaners

Publication: American Journal of Industrial Medicine, 53:743-756, 2010

Authors: B J Burgel, M C White, M Gillen, and N Krause

Tim Villnave, MSPH, is an ergonomics consultant in the Division of Risk Management for the State of Utah.