Loneliness, a silent epidemic haunting the world, has been linked to poor health and even early death. Now researchers from the United Kingdom and China have gone a step further to explain the association between loneliness and ill health.
They say loneliness and social isolation can impact the levels of proteins associated with various diseases and death. While loneliness is a state of distress or discomfort caused by whether someone ‘feels’ lonely, social isolation is a lack of social contact and relationships with others.
Let’s take a closer look.
How was the study conducted?
Researchers used data from over 42,000 people who participated in the UK Biobank project to analyse the ‘proteomes’, the entire set of proteins made by an organism.
With this, they were able to find out which proteins were present at higher levels in people who were socially isolated or lonely, and the link between these proteins and ill health, as per the University of Cambridge statement.
Researchers took into account factors like age, sex, education level, smoking and alcohol consumption. The study explored whether the 9.3 per cent of participants who reported social isolation and 6.4 per cent who reported loneliness had different levels of proteins in their blood than those who did not, as per The Guardian report.
The researchers deployed a method called Mendelian randomisation to study the relationship between social isolation and loneliness, as well as proteins.
The study, published in the journal Nature Human Behaviour, was carried out by researchers from the UK’s University of Cambridge and Fudan University in China.
“There are more than 100,000 proteins and many of their variants in the human body. AI and high throughput proteomics (the study of proteomes) can help us pinpoint some key proteins in prevention, diagnosis, treatment and prognosis in many human diseases and revolutionise the traditional view of human health,” Professor Jianfeng Feng from the University of Warwick said in a statement.
What did the study find?
The study found 175 proteins linked to social isolation and 26 proteins associated with self-reported
loneliness, many of which overlapped. About 85 per cent of the proteins associated with loneliness were also linked to social isolation.
“Many of these proteins are produced in response to inflammation, viral infection and as part of our immune responses, as well as having been linked to cardiovascular disease, type 2 diabetes, stroke, and early death,” the University of Cambridge said in a statement.
ADM is one of the proteins produced at higher levels when a person is lonely. According to previous studies, ADM has a role in responding to stress and regulating stress and social hormones, the statement read.
Another protein found in abundance was ASGR1, which is linked to higher cholesterol and an uptick in risk of cardiovascular disease. Other proteins identified play a role in the development of insulin resistance, cancer progression and so on.
As per The Guardian, researchers found that none of these proteins seemed to cause social isolation or loneliness.
Using the Mendelian randomisation technique, the researchers identified five proteins that become abundant due to loneliness.
“We found all these five proteins are related to numerous inflammation and metabolic markers,” said Dr Chun Shen, the first author of the research, from Fudan University in China, as per The Guardian.
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What have experts said?
The study highlights the importance of social relationships in an individual’s life. Loneliness and social isolation not only affect us mentally but also make us physically ill.
“The proteins we have 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,” Professor Feng said.
Speaking to The Guardian, Professor Marko Elovainio, of the University of Helsinki, who was not involved in the research, said the study supported previous works that showed that loneliness and social isolation (to some extent) were associated with various physical health issues, possibly due to systemic inflammatory processes induced by stress.
“A significant contribution of this study is that it now elucidates the biological mechanism – proteins – that may be responsible for the observed connections,” he said.
Experts say the study puts focus on the need to tackle social isolation and loneliness.
Professor Barbara Sahakian from the Department of Psychiatry at the University of Cambridge said in a statement, “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.”
With inputs from agencies