Lonliness causes illness
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 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.
The researchers say their findings suggest loneliness disrupts fight-or-fight signaling, which leads to increased production of immature monocytes, causing lower antiviral responses and increased inflammation. In turn, this may impair the production of white blood cells, partly explaining why lonely individuals are at greater risk for chronic illness.
The team demonstrated that such a mechanism can have severe implications for health. In a separate experiment, lonely monkeys with impaired antiviral gene expression that were infected with simian immunodeficiency virus (SIV) – the equivalent to HIV in humans experienced faster growth of the virus in their blood and brain.
The investigators conclude that further research is required to determine the exact mechanisms by which impaired norepinephrine signaling increases immature monocyte production. The team also wants to learn more about how loneliness increases the risk of poor health and how such outcomes can be prevented.
