British and Chinese researchers have discovered one of the mechanisms involved in the negative impact of loneliness and isolation on health.
- Researchers analyzed proteins from blood samples taken from more than 42,000 adults to understand how loneliness could impact health.
- They thus identified five proteins whose abundance was caused by loneliness.
- The team showed that loneliness is linked to a higher risk of heart disease, stroke and type 2 diabetes.
Heart disease, stroke, type 2 diabetes… numerous studies have revealed the harmful effects of loneliness on health. Researchers from the universities of Cambridge (United Kingdom) and Fudan (China) have managed to shed light on the mechanisms that lead social relationships to have an impact on the body. Their work was published in the journal Nature Human Behavior.
Loneliness and illness: proteins under the microscope
To try to understand how interactions with friends and family help us stay healthy, researchers had the idea of examining all the proteins present in the blood. They analyzed samples from more than 42,000 adults aged 40 to 69. Their social isolation and loneliness scores were calculated in parallel.
These elements allowed the team to identify 175 proteins associated with social isolation and 26 proteins with loneliness. “There was substantial overlap, with approximately 85% of proteins associated with loneliness being shared with social isolation”specifies the authors in their press release.
“Many of these proteins are produced in response to inflammation, viral infection and as part of our immune responses, in addition to having been linked to cardiovascular disease, type 2 diabetes, stroke and to premature death”they add.
Professor Jianfeng Feng, one of the leaders of the study, specifies: “The proteins we identified give us clues about the biology that underlies poor health in socially isolated or lonely people, highlighting why social relationships play such an important role in keeping us healthy.”
5 Proteins Increased by Loneliness
Secondly – using a statistical technique called Mendelian randomization – the team identified five proteins whose abundance was caused by loneliness. One of them is called ADM. It is associated with a reduced volume of the insular cortex (area of the brain that processes emotional and sensory information such as pain and self-awareness) as well as the left caudate nucleus (involved in emotional, reward and social processes). Higher levels of ADM are also linked to an increased risk of premature death.
Feeling lonely also impacts ASGR1 levels, according to the study results. This protein is associated with higher cholesterol levels and increased risk of cardiovascular disease. “The other proteins identified play a role in the development of insulin resistance, atherosclerosis and cancer progression, for example”specify the scientists.
“These findings highlight the importance of social contact to keep us well. More and more people of all ages report feeling lonely. This is why the World Health Organization has described social isolation and loneliness as a “global public health problem.” We need to find ways to tackle this growing problem and keep people connected to help them stay healthy.concludes Professor Barbara Sahakian from the University of Cambridge who worked on this research.
