Many people assume that stress contributes to the development of cancer, but it is far from proven.
Not only is the evidence mixed on general psychological stress, but there’s almost no research on whether work-related stress plays a role in cancer risk. Now, a large review of the literature, published on BMJ.com, has found no link between work stress and a number of common cancers.
Stress has been implicated in cancer because stress hormones can contribute to chronic inflammation, which has been shown to play a role in the promotion and progression of cancer.
Plus, stressed out people are more likely to smoke, drink alcohol and be overweight—lifestyle factors that have also been associated with an increased risk of some cancers.
Led by the Finnish Institute of Occupational Health and University College London, a consortium of researchers analyzed the results of 12 European studies conducted between 1985 and 2008 involving 116,000 participants aged 17 to 70. This is the largest study of its kind.
The authors measured levels of job stress, using four categories: high strain job (high demands and low control), active job (high demands and high control), passive job (low demands and low control) and low strain job (low demands and high control).
None of the participants had cancer when they entered the study. They were followed for an average of 12 years, with most studies lasting more than 10 years, and two studies lasting ,more than 20 years. The researchers collected data on cancer diagnoses during the course of the studies.
The good news: The meta-analysis found no evidence of an association between job stress and overall cancer risk or risk of colorectal, lung, breast, or prostate cancers. The authors suggested that many of the previously reported associations between work related stress and risk of cancer could have been influenced by chance or by small study size or other flaws in the study designs.
Certain factors such as shift work (there is some evidence of an association with risk of breast cancer) or other sources of psychological stress, may combine with work stress to increase cancer risk, but this was not examined in this study.
Prior research, for instance, has found a link between stress from adverse life events and an increased risk of breast cancer. In addition, work stress may contribute to other problems, like cardiovascular disease, so it’s important to try to reduce your level of work stress to improve your general health and well-being.
Laurie Tarkan is an award-winning health journalist whose work appears in the New York Times, among other national magazines and websites. She has authored several health books, including "Perfect Hormone Balance for Fertility." Follow her on Twitter and Facebook.