Feeling lonely? Researchers found that loneliness can cause significant health risk resulting to premature death; however, as to how this is connected remains unknown. They found that a person's sad mood could bring about cellular changes that can bring down the immune system.
Researchers from the University of Chicago headed by John Cacioppo studied 141 participants to analyze the connection between white blood cells and gene expression. Of the volunteers, chronic loneliness was identified in 36 of them.
Analysis revealed that in people with chronic loneliness, immune system, including leukocytes, is likely down. In fact, increased gene expression was evident in cells involved in inflammation and protection. "Leukocyte gene expression and loneliness appear to have a reciprocal relationship, suggesting that each can help propagate the other over time," researchers said. "These results were specific to loneliness and could not be explained by depression, stress or social support."
Cacioppo explained that the gene expression's pattern "is changing the body to be more likely to show an inflammatory response [that] puts the organism in a state of preparation for bacterial infection." In short, this means that people experiencing loneliness shift "away from protecting against viruses, and more towards protection against bacteria."
In a separate study on lonely macaque monkeys, the same pro-inflammatory shift pattern was seen. Furthermore, the shift was mostly linked to the increase of monocytes or immature cells. And this gene expression alteration reveals to have detrimental effects on monkey. To test, the team introduced a simian immunodeficiency virus in the monkeys. They found out that in lonely monkeys, the virus proliferated quickly in the blood and brain compared with those that are not lonely.
With these two studies in hand, "Both lonely humans and 'lonely like' monkeys showed higher levels of monocytes in their blood," researchers said. "The 'danger signals' activated in the brain by loneliness ultimately affect the production of white blood cells. The resulting shift in monocyte output may both propagate loneliness and contribute to its associated health risks."
