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.

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
Genome Biology (2007; 8 [9], Article R189) and is
available online at