While previous research has demonstrated the negative impact loneliness can have on health, the mechanisms underlying this association have been unclear. Now, a new study sheds light on the issue, finding that loneliness can alter immune system cells in a way that increases susceptibility to illness. Share on Pinterest Researchers say their study helps explain why loneliness can lead to poor health and early death. The study – published in the Proceedings of the National Academy of Sciences – was conducted by John T. Cacioppo, professor of psychology at the University of Chicago, and colleagues from the University of California-Los Angeles (UCLA) and the University of California-Davis. The research builds on a previous study conducted by Prof. Cacioppo last year, which found that older adults who experience extreme loneliness are at 14% greater risk for premature death. Another study reported by Medical News Today earlier this year expanded on such findings, revealing that loneliness and social isolation experienced at any age can increase the risk of early mortality. These studies and others say loneliness increases the risk for early death by triggering chronic illness, but Prof. Cacioppo and colleagues note that the molecular mechanisms underlying the health effects of loneliness are poorly understood.

Loneliness triggers CTRA gene expression in white blood cells Previously, the team found that people who were lonely had greater inflammation and a weaker immune response than those who were not lonely, suggesting loneliness may be associated with a mechanism known as “conserved transcriptional response to adversity” (CTRA). CTRA is characterized by an increase in expression of genes that play a role in inflammation and a decrease in expression of genes involved in antiviral response. Prof. Cacioppo and colleagues delved deeper in this latest study, analyzing the gene expression in leukocytes – white blood cells in the immune system that help stave off infection – of 141 adults aged 50-68 who were part of the Chicago Health, Aging and Social Relations Study. Confirming their previous research, the team found that individuals who were lonely demonstrated greater CTRA gene expression in their white blood cells than non-lonely individuals. However, they also found that loneliness predicted CTRA gene expression measured at least 1 year later, while CTRA gene expression predicted loneliness measured a year or more later. This indicates that leukocyte gene expression and loneliness work together to exacerbate each other over time.