Social relationships play an important role in our well-being. The findings in this study further demonstrate that both social isolation and loneliness are linked to poorer health and premature death. However, despite this evidence, the underlying mechanisms by which social relationships influence health remain unclear.
One way to explore biological mechanisms is to look at proteins circulating in the blood. Proteins are molecules produced by our genes and are necessary to help our bodies function properly. They may also serve as useful drug targets, allowing researchers to develop new treatments to combat diseases.
BLOOD SAMPLES OF 42 THOUSAND PEOPLE WERE EXAMINED
A team led by scientists at the University of Cambridge in the UK and Fudan University in China examined the proteomes (group of proteins) in blood samples donated by more than 42,000 adults aged 40-69 participating in the UK Biobank. This allowed the team to see which proteins were found at higher levels in people who were socially isolated or lonely and how these proteins were linked to poorer health.
THE INDIVIDUAL’S LONELINESS SCORES WERE CALCULATED
The team calculated social isolation and loneliness scores for individuals. Social isolation is an objective measure based on things like whether someone lives alone, how often they come into contact with others socially, and whether they participate in social activities. Loneliness, on the other hand, is a subjective measure based on whether an individual feels lonely.
SURPRISING RESULT
When the researchers analyzed the proteomes and adjusted for factors such as age, gender, and socioeconomic background, they found 175 proteins associated with social isolation and 26 proteins associated with loneliness (but there was significant overlap, with approximately 85% of the proteins associated with loneliness being shared with social isolation). Many of these proteins are produced in response to inflammation, viral infection, and as part of our immune responses, and have also been linked to cardiovascular disease, type 2 diabetes, stroke, and premature death.
The team then used a statistical technique known as Mendelian randomization to investigate the causal relationship between social isolation and loneliness, on the one hand, and the proteins, on the other. Using this approach, they identified five proteins associated with loneliness.
Dr. from the Department of Clinical Neurosciences at the University of Cambridge and the Institute of Science and Technology for Brain-Inspired Intelligence at Fudan University. Chun Shen said, “We know that social isolation and loneliness are linked to poorer health, but we have never understood why. Our study highlighted a number of proteins that play an important role in this relationship, and levels of some proteins in particular increased as a direct result of loneliness.” he said.
Professor Jianfeng Feng, from the University of Warwick, said: “There are more than 100,000 proteins and their many varieties in the human body. Artificial intelligence and high-throughput proteomics can help us identify some key proteins in the prevention, diagnosis, treatment and prognosis of many human diseases and provide insight into traditional studies of human health.” It can upset your perspective.” he said.
“The proteins we identified provide clues to the biology underlying poor health in socially isolated or lonely people and highlight why social relationships play such an important role in keeping us healthy.”
One of the proteins produced at higher levels as a result of loneliness is ADM. Previous studies have shown that this protein plays a role in responding to stress and regulating stress hormones and social hormones such as oxytocin, which can reduce stress and improve mood.
RISK OF EARLY DEATH
The team found a strong relationship between ADM and the volume of the insula, a brain center for interoception; The higher the ADM levels, the smaller the volume of this zone. Higher levels of ADM were also linked to lower volume of the left caudate, a region involved in emotional, reward and social processes. Additionally, higher ADM levels were linked to an increased risk of premature death.
Another of the proteins, ASGR1, has been associated with high cholesterol and increased risk of cardiovascular disease, while other proteins identified have been implicated in, for example, insulin resistance, atherosclerosis (‘fouling’ of the arteries) and cancer progression.
‘GLOBAL PUBLIC PROBLEM’
Professor Barbara Sahakian, from the Department of Psychiatry at the University of Cambridge, said: “These findings highlight the importance of social contact to keep us healthy. More and more people of all ages are reporting feeling lonely. That’s why the World Health Organization has identified social isolation and loneliness as a global public health problem “We must find ways to tackle this growing problem and keep people connected to help them stay healthy.” he said.