Researchers from the United Kingdom and China analysed blood samples from over 42,000 adults and discovered that individuals with stronger social relationships exhibited distinct protein profiles associated with improved immune function, according to a new study published in Nature Human Behaviour.
A team led by scientists from the University of Cambridge, UK, and Fudan University, China, investigated the ‘proteomes’ — the suite of proteins — in blood samples supplied by over 42,000 persons aged 40 to 69 years who are participating in the UK Biobank. This enabled them to determine which proteins were more prevalent in people who were socially isolated or lonely, as well as how these proteins were associated with poorer health. The team assigned social isolation and loneliness scores to people.
Social isolation is an objective metric based on factors such as whether someone lives alone, how frequently they interact with others socially, and whether they participate in social events. Loneliness, on the other hand, is a subjective metric that determines if a person feels lonely.
After controlling for age, gender, and socioeconomic status, the researchers found 175 proteins related with social isolation and 26 proteins associated with loneliness in the blood samples. Notably, almost 85 percent of the proteins related with loneliness coincided with those associated with social isolation.
Many of these proteins play roles in immunological function and inflammation, and they have been connected to a variety of health issues, including cardiovascular disease, type 2 diabetes, heart disease and stroke. Using a statistical technique known as Mendelian randomisation, the researchers discovered five proteins whose quantity was directly related to 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, stated, “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.”
Professor Barbara Sahakian of the Department of Psychiatry at the University of Cambridge stated, “These findings drive home the importance of social contact in keeping us well.
More and more people of all ages are reporting feeling lonely, which is why the World Health Organisation 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.”
