DNA StrandIn a small exploratory study, researchers have discovered a link between people who described themselves as lonely and genes linked to immune-system inflammation.

At the same time, DNA involved in systems that fight infection and spur disease-fighting proteins were less active in the lonely people. Identifying physical changes tied to social isolation opens new opportunities for care, the researchers said.

Immune system inflammation is the first response of a person’s immune system. The study focused on genetic influences on the body’s immune system, which creates antibodies and spurs controlled inflammation to fight foreign bacteria and viruses.

This study is apparently the first to directly connect how social factors are linked to an increased risk of cancer, heart disease, and viral infections.

“What this study shows is that the biological impact of social isolation reaches down into some of our most basic internal processes, such as the activity of our genes,” reported the study’s lead author Steve Cole, of the University of California at Los Angeles. “We found that changes in immune cell gene expression were specifically linked to the subjective experience of social distance.”

“We found that what counts at the level of gene expression is not how many people you know, it’s how many you feel really close to over time.”

Participants for the study were selected from a group of 153 who scored the highest and lowest on a test designed to assess whether they were happy or felt lonely, and whether their feelings of social isolation were short-lived, or they felt it was a lifelong condition.

Researchers at UCLA and the University of Chicago then used a new technology called DNA micro-arrays to survey the white blood cells genes from 14 people from the initial group over a 5-year period. Six study participants scored in the top 15 percent of the UCLA Loneliness Scale, the others scored in the bottom 15 percent.

The study found that in the six who scored highly on the loneliness measure that their genes were linked to producing antiviral and antibiotic responses and were not performing as well as in normal individuals. This means that people who feel socially isolated probably produce fewer cells to fight off invading bacteria and viruses.

Unfortunately, a compromised immune system often leads to poor health. And poor health and loneliness can be a self-perpetuating cycle. Sick individuals stay at home, or isolate themselves, which in turn makes them lonely. This study adds to the pre-existing literature about how social environmental influences impact health.

The findings indicate that the biological impact of loneliness is as great of a factor on poor health and even death rates as reduced social resources. The study observed immune system activation and antibody production, and found that leukocytes were differentially expressed in lonely individuals in comparison to those who were not. Leukocytes are white blood cells critical to the immune system. Future uses of the study include further exploration of the biological fingerprint to monitor interventions designed to reduce the impact of loneliness on health.

The study was published in Genome Biology.