Loneliness
Steve Cole and John Cacioppo, used a “gene chip” to look at the DNA of isolated people and found that people who described themselves as chronically lonely have distinct patterns of genetic activity, almost all of it involving the immune system.
The study does not show which came first — the loneliness or the physical traits.
Many studies of large populations have shown that people who describe themselves as lonely or as having little social support are more likely to die prematurely and to have infections, high blood pressure, insomnia and cancer.
When the researchers studied and compared all 22,000 human genes, 209 stood out in the loneliest people.
Many of the these genes seemed to be involved in the basic immune response to tissue damage and others were involved in the production of antibodies (the tag the body uses to mark microbes or damaged cells for removal), suggesting that the loneliest people had unhealthy levels of chronic inflammation, which has been associated with heart and artery disease, arthritis, Alzheimer’s, etc.