Lennart LeviLennart Levi, MD, PhD, Emeritus Professor of Psychosocial Medicine. Became Sweden’s first Professor of Psychosocial Medicine at the Karolinska Institute in Stockholm, Sweden, in 1978. In 1959 he founded and chaired the Karolinska’s Department of Stress Research, which in 1973 was designated the first World Health Organization Centre in this field. In 1980, he also founded and directed the National Swedish Institute for Psychosocial Factors and Health (IPM). During 1982-2005 he has been Chair of the Section on Occupational Psychiatry of the World Psychiatric Association and, since 2001, President of the International Stress Management Association. Before and after his retirement in 1995, he has been an advisor to WHO, ILO and the European Commission in his field.

Prof. Johannes Siegrist

Professor of Medical Sociology at the University of Düsseldorf
Work Package Leader ‘Fair Employment’
 

What have been the main academic issues your team has worked on in the past?

“Our team has worked for several years on what aspects of modern work and employment conditions are important for health. In the past, occupational medicine mainly focused on physical and chemical noxious stimuli at work, and issues like working in shifts and the effects of noise. Today there are many other challenges such as technological progress, the increase of the service sector (and therefore service sector occupations), rising competition due to globalisation of work and employment, and also increasing job insecurity. We have analysed the adverse effects of these aspects of modern work on the health of employees, in particular focusing on the socially unequal distribution of these aspects amongst the working population.

The best way to analyse these associations is to conduct cohort studies on employed people, and to follow them prospectively over a long period of time. Our research team has been involved in several such studies. However, cohort studies require a huge effort and because of the long lengths of time they necessarily take there is only relatively slow progress in terms of scientific knowledge.”

Is there already some evidence of the impact of increased competition in the globalised world on health?

“Yes, there is. In order to identify those components within the complex work environment that really matter for health, you first need to develop a theoretical model that will allow you to analyse such associations. Our research resulted in the “effort–reward imbalance model” (Siegrist, 1996). The idea behind this model is that in modern economies workers are often forced to put a lot of effort into their job and to work in highly competitive environments. The compensation for these efforts is, however, not always adequate and proportionate. Not only in terms of salaries but also in terms of job security, promotion prospects, and the credit and recognition given by supervisors.

Research has shown that this imbalance between effort and reward (‘high cost–low gain’) is associated with an elevated risk of depression (starting for the first time in life). It also shows that for these workers the relative risk of suffering from a coronary heart disease increases by 40-60 per cent. These are substantial effects which can thus be attributed to adverse work environments for health.”

Are there, besides the “effort–reward imbalance model” that you have developed, any other models being used to study the effects of the workplace on employee health?

“Yes, there are two other theoretical approaches that have been developed to analyse health adverse consequences in modern work, in which the physical and chemical hazards are not in the first line of analysis – even though they are still important.

The first approach, which is the oldest and best known, is the so-called “demand–control model”, developed by the American sociologist Robert Karasek (1979) and the Swedish epidemiologist Töres Theorell (Karasek & Theorell, 1990). The model defines work-stress in terms of specific task profiles, which are characterised by high demands and pressure, and low control and decision latitude. The “demand–control model” therefore analyses the health of workers in a different way but has health consequences similar to those described earlier. Therefore the health risk is cumulative for those people working under conditions that characterised by both the demand–control and effort–reward imbalance models. When exposed to multiple stressors, workers thus experience an additional burden on their health.

The second model, the “organisational justice model”, is more recent and examines the association between components of organisational justice (the justice of decision-making procedures and interpersonal treatment) and the health of employees (Greenberg, 1990). For example, it deals with unfairness in promotion procedures, mobbing (bullying) at work, and interaction conflicts. The model has not yet been tested as extensively as the other two models in prospective cohort studies.”

How do health inequalities fit into all of this and why are they important?

“Adverse psychosocial work environments are unequally distributed across the working population, leaving those at the lower end of society at higher risk of suffering from adverse health effects as a result of their working conditions. Lower-skilled people are more likely to have a job which has high demands and low control, and where rewards are relatively poor compared to efforts exerted. The prevalence of some major chronic diseases also exhibits a social gradient. For example, cardio-vascular diseases are more common amongst lower-educated and lower-status people than amongst managers and higher-skilled employees. Depression occurs twice as often amongst lower-skilled blue-collar workers as amongst higher-skilled white-collar workers, and manual labour is typically associated with a higher risk of work-related accidents. There are of course other factors – such as unhealthy behaviours – that also have an impact on the prevalence of diseases and risks at work, but it is a fact that a social gradient exists and that certain diseases affect those in lower socio-economic positions more frequently.

The following three relationships have been scientifically proven: (1) a low socio-economic position is related to a high health risk; (2) a low socio-economic position is related to a high frequency of stressful psychosocial work; and (3) stressful work is related to a high health risk.

A first approach addressing links between employment and health and explaining the social gradient is called the “mediation hypothesis”. This combines these three associations and states that stress at work mediates (at least partially) the statistical relationship between a low socio-economic position and a high health risk (such as coronary heart disease or depression).

The second approach is called the “moderation hypothesis”, which is built around the idea that stressful or unhealthy work has an impact on the health of employees at all levels. The strength of the effect, however, varies. People at the bottom of the social hierarchy experience a stronger effect of workplace stress on their health compared to people from higher up the social hierarchy. The explanation given by the “moderation hypothesis” for this phenomenon is that people living in more privileged situations have better resources available and are therefore better able to cope with adverse work environments.

Both hypotheses have been tested in various studies and both have been shown to be valid. However, further research is needed to reach firm conclusions about the extent to which they contribute towards explaining the social gradient of major stress-related diseases. The reason why findings are still inconclusive is because high quality scientific evidence is needed, which can only be provided by prospective research and cohort studies. Unfortunately, few such studies have been conducted so far. A small number of cohort studies have explored some of the aspects of the two hypotheses, but since different methods and measurements were used it is difficult to compare results. Additional prospective research would be highly desirable.”

So how does the DRIVERS project enrich your work and research?

“Firstly, as part of DRIVERS we will be performing systematic reviews to collect and bring together all current evidence on the links between working conditions, social inequalities and unequal health. This adds a new component to our work, as until now we have only been involved in original research rather than systematic reviews.

In addition to that, DRIVERS provides us with the important opportunity of working together with EuroHealthNet to increase the dissemination of available research, especially among policy makers. Awareness amongst policy makers on the links between employment conditions, health and the social gradient is often limited. However, intensive dissemination of existing knowledge can’t be done by a university alone, and European or international initiatives (such as the WHO European Review on Social Inequalities in Health) therefore offer great opportunities to bridge the gap between researchers and decision makers.

Finally, DRIVERS offers us the possibility of working closely together with civil society associations, and to learn more about the work of NGOs and other organisations that focus on employment conditions and the consequences of inequalities. We’ll be conducting the DRIVERS case study work together with Business in the Community; this type of collaborative work is new and quite exciting!”

How does collaboration between the three DRIVERS research components contribute to more comprehensive scientific approaches to analysing health inequalities?

“Until now our research has mainly focused on the working conditions of individual workers and companies. This type of research is – of course – contextualised by macro-level conditions like laws and labour market policies, and also by transnational economic developments such as budgetary cuts as a result of the economic crisis. DRIVERS provides us with the opportunity of broadening the research framework we work within and moving away from concentrating on single companies or single employees to analyse the broader social context.

For example, it will be interesting to collaborate with the DRIVERS work strand on Income and Social Protection work, which is led by Professor Olle Lundberg from the Centre for Health Equity Studies in Sweden (CHESS). He has been studying welfare regimes and social security arrangements in cross-national comparative settings, and through this collaboration we will be able to further reinforce and expand the multi-level approach our team is taking.

The other DRIVERS work strand, led by Professor Peter Goldblatt and his team at University College London (UCL), focuses on early childhood and is taking a life-course approach. Again, the work–health approach is normally a more narrow approach, concentrating on people who are in their mid-life or early old age life period. It is of course important to look into the developments and experiences of people earlier in their lives before they entered into employment. It would be interesting to study the impact of inequalities in early childhood on future life trajectory, selective recruitment processes, and opportunities to have a specific occupation. Early life acts as a selective mechanism in terms of where you end up in your professional career, and is therefore an important addendum to our approach. Because of our involvement in DRIVERS we will be able to discuss such life course aspects.”

Finally, if there were one outcome that you could ideally achieve by the end of the DRIVERS project, what would it be?

“Apart from successfully delivering the work we are involved in, it would be wonderful if we could demonstrate that an evidence-based work-related intervention is capable of reducing the burden of disease in working populations and thus reduce health inequalities. This would be an ideal outcome! But it is also an outcome that is still a dream, and in order to test how realistic such a dream is we have to do some hard work.”

References:

• Siegrist J (1996) Adverse health effects of high effort/low reward conditions. J Occup Health Psychol 1: 27-41
• Karasek R, Theorell T (1990) Healthy Work. New York: Basic Books
• Greenberg J (1990) Organizational justice-yesterday, today, and tomorrow. J Manag 16:  399-432