Comparison of the “Instability of Pyramids of Stress (IPS)”,
the “Job Strain (JS)”, and the “Effort–Reward Imbalance (ERI)” Models: Assessing Occupational Health and Work Environment Stressors in Dentists and Cleaners

Reza Emdad

Karolinska Institute, and the National Institute for Psychosocial Medicine (IPM), Stockholm, Sweden

Corresponding author: Reza Emdad, Ph.D (Dr.Med.Sci.), Associate Professor
    Karolinska Institute and the National Institute for Psychosocial Medicine
    P.O. Box 230
    S-17177 Stockholm, Sweden
    Telephone: Phone: 46 8 524 8 6951
    Fax number: 46 8 34 41 43
    E-mail: reza.emdad@ipm.ki.se

CEJOEM 2005, Vol.11. No.1.: 33–71

Key words:
Ergonomics, occupational stress models, instability of pyramids of stress, IPS, job strain, effort–reward imbalance, health, family

Abbreviations:
CVD
ERI
IPS
IRWSP
ISWSP
IRWD		 = Cardiovascular disease
= Effort–reward imbalance
= Instability of pyramids of stress
= Instability of reward-weighted stress pyramid
= Instability of satisfaction-weighted stress pyramid
= Instability of reward-weighted demand		 IRWSP
ISWD
ISWSP
JS
RWD
SWD		 = Instability of reward-weighted stress pyramid
= Instability of satisfaction-weighted demand
= Instability of satisfaction-weighted stress pyramid
= Job strain
= Reward-weighted demand
= Satisfaction-weighted demand

Abstract:
Criticisms have been made concerning existing job stress models: the job strain (JS) and the effort–reward imbalance (ERI) models. The concept of total burden of exposure to occupational stressors – including psychosocial elements, neuroergonomics, home and family factors – is presented, and the instability of pyramids of stress (IPS) model, which integrates these into a single model focused upon health, and the problem of burnout, problems with short term memory, and cardiovascular system, is elaborated. In order to assess occupational health and pinpoint where the prevention and intervention was most effective in the work environment, the IPS, which is a new occupational stress model, was empirically tested. The JS, the ERI, and the IPS models were applied in a group of dentists compared to a group of cleaners in order to show differences between these two groups with regard to health and work environmental stressors, and critically compare these three models with each other. Quantitative information about the dentists’ and professional cleaners’ work environment and health was collected using questionnaires based on these three models; the results were compared with each other. The reliability of the IPS was within the acceptable range. The results showed that IPS, i.e., “the total occupational burden,” was significantly higher in the dentist group compared to the cleaners. The ERI model showed no significant intergroup difference, but the demand/control model showed higher job strain in the cleaner group compared to the dentists. This was opposite to the results obtained by using the IPS model. Neither the JS nor the ERI models showed any significant correlations with the indices of sleep disturbances and musculoskeletal pain in neither the dentist nor the cleaner groups. But there were significant correlations between the IPS and the indices of sleep disturbances and musculoskeletal pain in the dentist group. The accumulative adverse effects, caused by the “home and family factors” were significantly higher in the dentists compared to the cleaners. Fixed characteristics and modifiable features of the work environment of dentists and cleaners were pinpointed using the IPS intervention matrix. This was to assess were the focus of intervention could be most effective in reducing risk of cardiovascular disease, burnout and short-term memory problems. In conclusion, the present paper represents a step in the development of a new occupational stress model that holds promise for future occupational stress prevention and health promotion strategies.

Received: 23 January 2004
Accepted: 2 August 2005
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