Loneliness triggers disease-linked protein changes in the blood: Study

Are you someone who stays disconnected from your family, friends, and loved ones? Is loneliness haunting you? Well, new research suggests that loneliness can not only affect your mental health, but also increase your risk of developing heart disease, stroke, type 2 diabetes, and even make you more susceptible to infections.
According to a study published in the journal Nature Human Behaviour, social relationships are crucial for our overall well-being. Researchers from the University of Cambridge, UK, and Fudan University, China, studied proteins from blood samples taken from over 42,000 adults aged 40-69 years recruited to the UK Biobank, and they found that loneliness is linked with poor health and early death. Social isolation and loneliness have a huge impact on our overall well-being.

Despite this evidence linking social relationships to health, the biological mechanisms behind it remain unclear. Understanding the proteins circulating in the blood is crucial for knowing this biological mechanism. They can also serve as useful drug targets, thereby opening the possibility of new drugs for the diseases.

The researchers examined the ‘proteomes’, the suite of proteins in the blood samples, and found that proteins were present at higher levels in people who were socially detached and lonely. They also studied how these proteins are linked to ill health.
“We know that social isolation and loneliness are linked to poorer health, but we’ve never understood why. Our work has highlighted a number of proteins that appear to play a key role in this relationship, with levels of some proteins, in particular, increasing as a direct consequence of loneliness,” Dr. Chun Shen from the Department of Clinical Neurosciences at the University of Cambridge and the Institute of Science and Technology for Brain-Inspired Intelligence, Fudan University, said in a statement.

Professor Jianfeng Feng from the University of Warwick added, “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 the prevention, diagnosis, treatment, and prognosis of many human diseases and revolutionize the traditional view of human health. The proteins we’ve identified give us clues to the biology underpinning poor health among people who are socially isolated or lonely, highlighting why social relationships play such an important part in keeping us healthy.”
ADM is one of the proteins produced at higher levels due to loneliness. Previous studies have shown the role of this protein in responding to stress and regulating stress hormones and social hormones such as oxytocin. Higher levels of ADM were linked to an increased risk of early death.

ASGR1, another protein is linked with higher cholesterol and an increased risk of cardiovascular disease. Other proteins identified play a role in the development of insulin resistance, atherosclerosis (‘furring’ of the arteries), and cancer progression.

“These findings drive home the importance of social contact in keeping us well. More and more people of all ages are reporting feeling lonely. 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,” Professor Barbara Sahakian from the Department of Psychiatry at the University of Cambridge said.