Göran Fahlén

Effort-Reward Imbalance at Work and Incident Coronary Heart Disease A Multicohort Study of 90,164 Individuals

Background: Epidemiologic evidence for work stress as a risk factor for coronary heart disease is mostly based on a single measure of stressful work known as job strain, a combination of high demands and low job control. We examined whether a complementary stress measure that assesses an imbalance between efforts spent at work and rewards received predicted coronary heart disease. Methods: This multicohort study (the “IPD-Work” consortium) was based on harmonized individual-level data from 11 European prospective cohort studies. Stressful work in 90,164 men and women without coronary heart disease at baseline was assessed by validated effort–reward imbalance and job strain questionnaires. We defined incident coronary heart disease as the first nonfatal myocardial infarction or coronary death. Study-specific estimates were pooled by random effects meta-analysis. Results: At baseline, 31.7% of study members reported effort–reward imbalance at work and 15.9% reported job strain. During a mean follow-up of 9.8 years, 1,078 coronary events were recorded. After adjustment for potential confounders, a hazard ratio of 1.16 (95% confidence interval, 1.00–1.35) was observed for effort–reward imbalance compared with no imbalance. The hazard ratio was 1.16 (1.01–1.34) for having either effort–reward imbalance or job strain and 1.41 (1.12–1.76) for having both these stressors compared to having neither effort–reward imbalance nor job strain. Conclusions: Individuals with effort–reward imbalance at work have an increased risk of coronary heart disease, and this appears to be independent of job strain experienced. These findings support expanding focus beyond just job strain in future research on work stress.

The Effort-Reward Imbalance model of psychosocial stress at the workplace—a comparison of ERI exposure assessment using two estimation methods

It is not unusual for old data to be used in epidemiological studies. Recently developed instruments for measuring work-related stress did not exist when the data collection was carried out. Therefore, approximate questions are sometimes used. An apparent problem is the lack of validation of proxy questions. The aim of this study was to compare the original questions for measuring Effort-Reward Imbalance (ERI) with approximate questions. The study population corresponded with a subgroup in the WOLF-n (WOrk, Lipids, Fibrinogen–north) cohort study of cardiovascular risk in a working population in the north of Sweden: 655 men and 178 women. The agreement in exposure between the original and the approximate ERI single questions was relatively low throughout, whereas the correlation between the ERI subscales and the ERI ratios was reasonable. The latter agreement between the original and the approximate ERI ratio indicates that the approximate measures might have been useful in the past. Yet, whenever possible the implementation of the original questionnaire in study protocols is recommended since a complete measurement of ERI might help to further improve the internal consistency and the predictive validity of this exposure to effort-reward imbalance.

Work overcommitment: Is it a trait or a state?

PurposeEffort–reward imbalance (ERI) is a well-tested work-related stress model with three components, the two extrinsic components “efforts” and “rewards” and the one intrinsic component “overcommitment”. While an imbalance between “efforts” and “rewards” leads to strain reactions, “work-related overcommitment” (OC) has been described as a personal characteristic with a set of attitudes, behaviours, and emotions reflecting excessive striving combined with a strong desire for approval. However, the question whether OC is a personality trait or a response pattern sensitive to changes in the work context (state) is still open.Methods2940 Swedish industrial employees were included in this longitudinal analysis of the WOLF-Norrland data over 5 years. A change of OC index or its subscales were regressed against a change of freedom of choice at work, extra work, and ERI adjusted for age, sex, and education.ResultsWhile OC was insensitive to changes in freedom of choice at work and extra work, it was clearly associated with changes of work-related stress over time. Three of four OC subscales exhibited statistically significant associations with ERI.ConclusionsFor the first time, we studied fundamental characteristics of OC as an independent personality variable (trait) or an outcome variable subject to changes in the work environment (state). The association between external ERI and OC over time supports our hypothesis of OC being a state. Further investigations are needed to establish OC as a trait or a state.