- Poor psychological health leading to physical illness
(psychosomatic illness) has been known since centuries.
- Very little research data available on the role of psychological
distress in cancer deaths.
- This large prospective cohort study looks at the association
between psychologic distress and cancer deaths.
prolonged state of poor mental health or
psychological distress could increase the rates of death due to cancer
according to a large analysis of pooled data from 16 prospective cohort studies
initiated between 1994-2008 in the UK.
for the Study
- Very little published data is currently available on the association between
psychological health and cancer.
- The few prospective studies that have attempted to do so are
small in size and have thrown up widely differing results ranging from
positive, neutral and negative associations.
- Some of the earlier studies have not explained satisfactorily,
the confounding factors that could affect the results such as
socioeconomic status, risky health behavior and systemic inflammation.
of the Study
for the study were chosen from nationally representative samples from the
health survey of England (13 studies) and the Scottish health survey (3
participants included 163,363 men and women aged 16 or older
at the start of the study, who were cancer free to begin with, provided
self-reported poor mental health scores (based on the general health questionnaire,
GHQ-12) and agreed to linkage of their health records.
‘Psychological distress is a potential predictor for cancer mortality rates.The risk of anxiety and depression in causing certain cancers has been found to be as same as smoking and obesity for cancers.’
Details such as height and weight, body mass index (BMI)
, educational and
socioeconomic status, smoking and drinking behaviors were also collected.
on the questionnaire to assess psychological distress, the participants were subdivided into 4 groups
for comparison namely:
data regarding the psychological state of the participants was collected on 4
separate occasions spanning a maximum of 19 years surveillance. Participants
were asked about their mental status in the preceding four weeks in the
remove effect of reverse causality, i.e. presence of cancer-causing
psychological distress, persons who had cancer initially and those who died
within the first 5 years of follow-up were excluded from the study.
the Study Found
- Persons who were highly distressed had higher death rates from
specific cancers compared to minimally distressed persons.
- The strongest associations were found for carcinoma of the
colorectum, pancreas, prostate, and esophagus and for leukemia.
- Interestingly, for cancers of the prostate and colorectum, a gradient was seen i.e. the greater the
degree of distress, the higher the mortality rates, partially supporting a causal influence hypothesis.
- Except for lung cancer, where smoking is known to have a
risk association, the hazard ratios of stress in the causation of cancers
was found to equal the magnitude of smoking and obesity for selected
Mechanisms How Stress Might Lead to Cancer Deaths
effect of stress on cancer could be related
(etiology) or survival
(prognosis). Additionally, these effects can be direct (biological) or indirect
(behavior related) and could be responsible for specific cancers and/or
multiple cancers. These mechanisms include the following.
- Prolonged stress can cause disordered
immunity and as a result affect tumor protective responses leading to
causation of cancer.
- Immune dysregulation has been known to cause a more unfavorable outcome in cancers
such as cancer of the colorectum, stomach, lung, and mesothelium.
- Stress has been found to increase
hormone-related cancers such as prostate and ovarian
cancers, possibly by disruption of the hypothalamic
pituitary adrenal (HPA)and sympathetic adrenal medullary (SAM)
- Stressed persons are more likely
to indulge in excessive smoking or alcohol intake and lead a sedentary
life, all of which might increase cancer risk. However, this study made due
adjustments for these factors during analysis.
- Stressed individuals might possibly delay seeking medical
attention or be irregular with treatment, resulting in a poorer
Merits and Demerits of the Study
- The chief merits of the study included
the usage of raw unpublished data of the general population and using a
large and well-defined
- Possible limitations include the
short reference period of four weeks to assess the mental status, though
this was done on four separate occasions.
- The specific cancer outcomes analyzed in the
study were not hypothesis driven.
- Presence of confounding factors is a
strong possibility in observational studies such as this.
Conclusions from the Study
This study offers additional evidence
that psychological stress could increase death rates from cancer.
The authors suggest that while using
multifactorial algorithms to assess the risk of causing disease such as cancer,
psychological stress must also be employed as a component, which is currently
not the case. Assessing these collective risk factors will have better
predictive value regarding the outcome.
Further research is necessary to
establish a causal association between psychological distress and cancer.
- G David Batty, Tom C Russ, Marjorie MacBeath, Emmanuel Stamatakis,Mika Kivimäki, 'Psychological distress in relation to site specific cancer mortality: pooling of unpublished data from 16 prospective cohort studies' BMJ 2017; 356 doi: https://doi.org/10.1136/bmj.j108