Scientists have long known that people who suffer from loneliness or social isolation have a higher mortality rate than people who don’t. What has not been known is whether loneliness has a direct biological impact on health or whether the effect is indirect, stemming from the fact that lonely people have fewer social resources (e.g., physical or economic help). Now, for the first time, researchers at the University of California at Los Angeles (UCLA) have identified a biological link between loneliness and overactivity in genes that adversely impact the immune system, increasing inflammation; they have also found a biological link to underactivity in genes that offer a protective effect through antiviral and antibody production.
Lead study author Steve Cole, PhD, associate professor of medicine in the division of hematology and oncology at David Geffen School of Medicine at UCLA, said, “What this study shows is that the biological impact of social isolation reaches down into some of our most basic internal processes—the activity of our genes. We found that changes in immune cell gene expression were specifically linked to the subjective experience of social distance,” said Cole. “The differences we observed were independent of other known risk factors, such as health status, age, weight and medication use. The changes were even independent of the objective size of a person’s social network.”The study was published in the open-access journal Genome Biology (2007; 8 , Article R189) and is available online at http://genomebiology.com/2007/8/9/R189.