Loneliness linked to cancer in rats
Loneliness and stress are more likely to cause breast cancer, a study using rats suggests.
A team studied the difference between isolated rats and rats living in a social group. They separated newborns from groups and found that isolated rats had a greater risk of developing tumours which were more deadly. The isolation causes the rats to produce a higher amount of the stress hormone, corticosterone. Receptors that recognise this hormone were found in the tumour, directly feeding it, highlighting the link between the two.
Previous research has shown that stress can activate cancer inducing genes in humans. More research is needed to show whether these results are also seen in humans, however.
Scientists think this finding may begin to explain why women in high crime neighbourhoods seem to develop breast cancer earlier and why patients with psychiatric disorders have a shorter lifespan. They believe the results apply beyond breast cancer in explaining the effects of social networks in protecting health.