The biological price of loneliness may be steeper than previously thought. Scientists have identified specific proteins in blood that could explain why socially isolated people face higher risks of heart disease, stroke, and other health problems, according to research published in Nature Human Behaviour.
In a study of over 42,000 adults, researchers at the University of Cambridge and Fudan University found that both social isolation and feelings of loneliness are linked to changes in proteins that control inflammation and immune responses. These changes may help explain why social connections are so vital for human health.
The research team found 175 proteins associated with social isolation and 26 proteins linked to loneliness. Many of these proteins are involved in the body’s response to inflammation and viral infections, as well as being connected to cardiovascular disease, type 2 diabetes, and stroke.
“We know that social isolation and loneliness are linked to poorer health, but we’ve never understood why,” explained Dr. Chun Shen from the Department of Clinical Neurosciences at Cambridge. “Our work has highlighted proteins that appear to play a key role in this relationship.”
The findings gain urgency as social isolation becomes a growing public health concern. “More and more people of all ages are reporting feeling lonely,” said Professor Barbara Sahakian from Cambridge’s Department of Psychiatry. “That’s why the World Health Organization has described social isolation and loneliness as a ‘global public health concern.’ We need to find ways to tackle this growing problem and keep people connected to help them stay healthy.”
The study also revealed that one protein in particular – ADM – appears to play a crucial role. Higher levels of ADM were associated with increased risk of early death and changes in brain regions involved in emotional and social processes. This provides new insights into how loneliness might affect both brain and body.
Professor Jianfeng Feng from the University of Warwick emphasized the scale of potential impacts: “There are more than 100,000 proteins and many of their variants in the human body. AI and high throughput proteomics can help us pinpoint some key proteins in prevention, diagnosis, treatment and prognosis in many human diseases.”
This research opens new possibilities for understanding how social connections influence health at a molecular level. The identified proteins could potentially serve as targets for new treatments or as early warning signs of health risks in socially isolated individuals.