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Lots of studies have suggested stress can be a cause of ill health – and that leads to people ceasing to work before they reach retirement age. But most have offered only a snapshot on the issue. José Ignacio Cuitún Coronado and Tarani Chandola from the University of Manchester describe a major new study, which has shed new light on how work stress can affect an employee’s health over a longer period.
Many animals have the ability to adapt to environmental changes and pressures so that they’re better prepared the next time they happen. Bears can put on fat as winter approaches, for instance, to help them stave off hunger and stay warm.
And human beings can do this too. Stressful situations trigger chemical responses which can help to give us extra resources when things are tough. Our neuroendocrine systems, for instance, trigger hormonal responses which enhance our physical performance when we need it most.
But these valuable systems can have a down-side. In our research, we wanted to look at how repeated exposure to stressful situations might contribute to health problems, particularly in people nearing the end of their working lives. We call this stress-induced effect ‘Allostatic Load’ – the “wear and tear” on the body that accumulates as an individual is exposed to repeated or chronic stress because of fluctuating hormonal responses.
Given that many governments are looking for ways to extend working lives, there’s particular interest in finding out how stress can affect the health of older workers. We were able to tap into a rich source of information – the English Longitudinal Study of Ageing (ELSA), which has followed a representative sample of almost 10,000 over-50s since 2002.
These participants have been interviewed regularly and one of the things they’ve been asked to report is whether they’ve experienced a sense of imbalance between the effort they put into their jobs and the rewards they get out.
This gave us a sample of 2663 older adults, all over 50 and living in England, who’d reported these feelings at least once and who’d been assessed as having had an adverse reaction to them. We wanted to know whether repeated episodes had a bigger effect than just one, and whether the effect would be just as strong for past episodes as it was for more recent ones.
Health testing
Between 2004-5 and 2014-16 the group were asked about stress at work, but they also underwent physical tests to see how the various systems in their bodies were bearing up.
They were visited by nurses who carried out a battery of tests including taking hair samples to assess levels of the stress-related hormone cortisol, carrying out blood pressure checks to provide information on their cardio-vascular systems, white blood cell counts to assess their immune systems and cholesterol checks on their metabolic systems. Participants also had measurements taken of their waist to height ratios – a good indicator of coronary heart disease risk factors.
Overall, we found the more occasions of work-stress a participant had reported, the greater their ‘Allostatic Load’ index – that is, the greater the amount of biological wear and tear.
Moreover, the evidence suggests that employees who had experienced stress more recently, towards the end of their working lives, had higher levels of health risk when compared to those who had experienced it earlier in their careers.
This suggests there is an association between repeated reports of stress at work and biological stress mechanisms, which in turn could lead to stress-related disorders such as coronary heart disease, type 2 diabetes or depression. This also suggests that previous cross-sectional studies which reported small or inconsistent associations may have suffered because they were only measuring one effect at one time.
Work-related stress is one of the reasons for labour market exit – and our findings would suggest that earlier, snapshot studies may have underestimated the true effect of work-related stress on health over a lifetime.
As this is an observational study, we cannot make any causal claims. There may be other factors that we have not taken into account that may explain the association between stress and disease risk. For example, sleep problems may be relevant – though they may also be part of the journey from stress to ill-health.
But equally it is possible that cumulative exposure to work stress is resulting in damage to employees’ physical health, which is then leading to disability and an early exit from the world of work. So, if we want to extend working lives then reducing work-related stress could be one of the keys to achieving that goal.
Allostatic Load and Effort-Reward Imbalance: Associations over the Working-Career, by José Ignacio Cuitún Coronado, Tarani Chandola and Andrew Steptoe, is published in the International Journal of Environmental Research and Public Health.