New research published in Nature Human Behaviour reveals that strong social relationships can enhance the immune system and reduce the risk of chronic diseases like heart disease, stroke, and type 2 diabetes. Researchers from the UK and China studied blood samples from over 42,000 adults, uncovering distinct protein profiles linked to stronger immune function in individuals with robust social ties.
Led by scientists from the University of Cambridge and Fudan University, the study analyzed ‘proteomes,’ or protein suites, from participants in the UK Biobank. These individuals, aged 40-69, allowed researchers to explore how social isolation and loneliness impact health. The study focused on identifying proteins present in higher levels among socially isolated or lonely individuals, revealing a significant connection between these proteins and poorer health outcomes.
The researchers calculated social isolation based on objective measures—such as living alone, social contact frequency, and participation in social activities. Loneliness, in contrast, was assessed subjectively, based on whether individuals felt lonely. After adjusting for factors like age and socioeconomic background, the study identified 175 proteins linked to social isolation and 26 linked to loneliness. Remarkably, about 85% of the proteins associated with loneliness also overlapped with those related to social isolation.
Many of these proteins play crucial roles in immune function and inflammation, which are associated with health conditions such as cardiovascular disease, type 2 diabetes, and stroke. Through Mendelian randomization—a statistical technique—the researchers pinpointed five proteins whose levels were causally linked to loneliness.
Dr. Chun Shen, from the University of Cambridge and Fudan University, explained that while the connection between social isolation, loneliness, and poor health was known, the study helped uncover the underlying mechanisms. Some proteins, including ADM (adrenomedullin), were found to increase as a direct result of loneliness. ADM is involved in stress response and regulates stress hormones like oxytocin. Elevated ADM levels were also associated with smaller brain regions related to emotional processing and a higher risk of early death.
Professor Barbara Sahakian from the University of Cambridge emphasized the importance of social connections for maintaining well-being. She pointed out the rising rates of loneliness across all age groups, which the World Health Organization has termed a “global public health concern.” The study’s findings highlight the urgent need to address loneliness and social isolation to promote better health outcomes and well-being.
This research provides compelling evidence that fostering strong social bonds can be a powerful tool for improving public health, reducing chronic disease risks, and enhancing immune function, urging greater focus on social connectivity in healthcare strategies.
