Study finds social isolation could cause physical inflammation

Social isolation could be associated with increased inflammation in the body, according to new research from the University of Surrey and Brunel University London in England and published in the journal Neuroscience & Biobehavioral Reviews.

For the study, researchers investigated the link between social isolation and loneliness with inflammation in the body. Analyzing 30 previous studies in this area, researchers found that social isolation could be linked to increased inflammation in the body.

Inflammation is the body's way of signaling the immune system to heal and repair damaged tissue, as well as defending itself against viruses and bacteria. Inflammation can eventually start damaging healthy cells, tissues, and organs and lead to an increased risk of developing non-communicable diseases such as cardiovascular disease, the researchers said.

The researchers found that social isolation, the objective state of being isolated from other people, was associated with the presence of c-reactive protein, a protein substance released into the bloodstream within hours of a tissue injury, and increased levels of the glycoprotein fibrinogen, which is converted into fibrin-based blood clots.

Additionally, the researchers also identified that the link between social isolation and physical inflammation was more likely to be observed in males than females. Further work is needed to clarify why this might be, but previous work suggests that males and females might respond differently to social stressors, according to the researchers.

The link between loneliness and inflammation was less clear-cut with results indicating a possible link between loneliness and the pro inflammatory cytokine IL-6. This finding was not consistent across the studies examined. Taken in combination with previous knowledge, it is likely that loneliness changes how the inflammatory system responds to stress rather than directly impacting inflammatory response, according to Kimberley Smith, PhD, lead author of the study and lecturer at the University of Surrey.

"Loneliness and social isolation have been shown to increase our risk of poorer health,” said Smith in a statement. “Many researchers propose that part of the reason for this is because they influence the body's inflammatory response. The evidence we examined suggests that social isolation may be linked with inflammation, but the results for a direct link between loneliness and inflammation were less convincing. We believe these results are an important first step in helping us to better understand how loneliness and social isolation may be linked with health outcomes."