New paper published in Psychological Medicine explores contributory factors linking mental health to cancer – and draws stark conclusions.
The authors of a new academic paper set themselves a challenge: to better understand how anxiety and depression are linked to cancer. To do so, they worked from a huge set of anonymised data: some 319,613 individuals within 18 cohorts of the Psychosocial Factors and Cancer Incidence consortium that had some measure of anxiety or depression; 25,803 of these individuals had cancer.
The researchers then looked for incidence of particular ‘health behaviours’, such as alcohol use, body mass index (BMI), physical inactivity, sedentary behaviour, sleep duration and quality, and smoking. From this, the researchers calculated a ‘hazard ratio’ for each factor.
Hazard ratios are frequently used in research into cancer. They work by comparing the results of people who undertook a particular treatment or intervention with those who did not. If the hazard ratio is ‘1’, there is no difference between the two groups of people. A hazard ratio less than or more than 1 means outcomes were different – and the greater the difference expressed in the ratio, the greater the difference in outcome. That in turn suggests the relative impact of the treatment or intervention.
So, what did this new study show?
- Read the full paper: ‘The mediating role of health behaviors in the association between depression, anxiety and cancer incidence: an individual participant data meta-analysis’
People with anxiety and depression had a very slightly higher association with cancer generally where some other factors were present: alcohol use, higher BMI, physical inactivity and smoking. But hazard ratios here were below 1.01.
For those with anxiety or depression who developed smoking-related cancers, the hazard ration for smokers ranged between 1.03 and 1.06 compared to non-smokers, suggesting a much stronger association. For lung cancer in particular, the hazard ratio was 1.04 to 1.10, while physical inactivity also had a significant result, with a hazard ratio ranging from 1.01 to 1.02.
Basically, those with anxiety or depression who also smoke have a between 3% and 10% greater chance of developing lung and smoking-related cancers.
‘Our findings underline the importance of smoking cessation interventions for persons with depression or anxiety,’ conclude the authors of the paper.
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