Researchers from the University of Chicago have discovered that socially isolated people are more likely to die earlier than their peers because they have a weaker immune system, according to a new study.
People that don’t spend much time interacting with others have a 14 percent higher chance of dying earlier than their peers – as they seem to have lower counts of white blood cells in their body.
White blood cells play an important role in the human body – helping to fight off disease and illness.
The researchers from the University of Chicago found that loneliness causes a fight-or-flight reaction in the body, which can result in the production of fewer white blood cells – weakening the immune system.
They examined gene expression in leukocytes, the cells responsible for the body against invading bacteria and viruses.
The scientists built their research on the findings of a previous study, which found a link between being lonely and a phenomenon known as ‘conserved transcriptional response to adversity’ (CTRA). This describes the link between lower immune system responses in lonely people, compared with those who have a healthy social life.
The phenomenon occurs due to an increase in the number of genes involved in an inflammation and when the number of genes involved in an antiviral response decreases.
The current study revealed that future CTRA gene expression could be predicted in lonely people over a year later. They also found that being loneliness and leukocyte seemed to aggravate each other as time passed.
The researchers then tested their research on primates, finding that those who displayed lonely tendencies also displayed higher CTRA activities.
When they dug a bit deeper into the occurrence, they found that these primates also displayed higher levels of norepinephrine – or the fight-or-flight neuro transmitter.
Other studies have shown norepinephrine cause stem cells present in bone marrow to create an immature monocyte – or a particular kind of immune cell that have higher levels of inflammatory gene expression and correspondingly low levels of antiviral genes.
When the researchers tested blood samples taken from socially isolated humans and primates they found that both showed high levels of monocytes.
Following this discovery, the researchers then followed the progression of simian immunodeficiency virus (the equivalent of HIV) in primates that were isolated from others.
They observed that the altered antiviral gene expression the isolated primates caused the disease to grow faster in the blood and brain.
Professor John Cacioppo said in a news release: “Taken together, these findings support a mechanistic model in which loneliness results in fight-or-flight stress signalling, which increases the production of immature monocytes, leading to up-regulation of inflammatory genes and impaired anti-viral responses.
“The ‘danger signals’ activated in the brain by loneliness ultimately affect the production of white blood cells,” Cacioppo said. “The resulting shift in monocyte output may both propagate loneliness and contribute to its associated health risks.”
The researchers stressed that their findings were independent of other factors including depression, stress and social support.
The study was published in the journal Proceedings of the National Academy of Sciences.