Loneliness significantly increases the risk of developing breast cancer, American scientists have claimed.
Researchers from the Yale University and the University of Chicago found that social isolation raises levels of a hormone which helps to trigger tumour growth.
They found that female rats who were kept in solitude were three times more likely than others to go on to develop the cancer, journal Proceedings of the National Academy of Sciences reported.
"This study offers insight into how the social world gets under the skin," said lead author Gretchen Hermes from Yale University. Co-author Martha McClintock from the University of Chicago added: "We need to use these findings to identify potential targets for intervention to reduce cancer and its psychological and social risk factors". "In order to do that, we need to look at the problem from a variety of perspectives, including examining the sources of stress in neighbourhoods as well as the biological aspects of cancer development," they said.
Reducing feelings of loneliness could potentially cut the numbers affected, the team behind the latest study believes, The Telegraph said.
Their findings show that levels of a stress hormone called corticosterone increased the rats who were kept in isolation and this hormone affects how cells grow, creating tumours.