Study Unveils Link Between Loneliness and Higher Risk of Heart Disease, Stroke - Video

New research found that interactions with friends and family may keep us healthy because they boost our immune system and reduce our risk of diseases such as heart disease, stroke, and type 2 diabetes. Their findings are published in the journal Nature Human Behaviour.

A team led by scientists examined the ‘proteomes’ – the suite of proteins – in blood samples donated by over 42,000 adults aged 40-69 years who are taking part in the UK Biobank. This allowed them to see which proteins were present in higher levels among people who were socially isolated or lonely, and how these proteins were connected to poorer health.

The team calculated social isolation and loneliness scores for individuals.

When they analysed the proteomes and adjusted for factors such as age, sex, and socioeconomic background, the team found 175 proteins associated with social isolation and 26 proteins associated with loneliness (though there was substantial 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, as well as having been linked to cardiovascular disease, type 2 diabetes, stroke, and early death.

They also identified five proteins whose abundance was caused by loneliness.

One of the proteins produced in higher levels as a result of loneliness was ADM. The team found a strong association between ADM and the volume of the insula, a brain hub for interoception, our ability to sense what's happening inside our body. In addition, higher levels of ADM were linked to increased risk of early death.

Another of the proteins, ASGR1, is associated with higher cholesterol and an increased risk of cardiovascular disease, while other identified proteins play roles in the development of insulin resistance, atherosclerosis (‘furring’ of the arteries) and cancer progression, for example.

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, said: “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.

Reference: Shen, C., Zhang, R., Yu, J. et al. Plasma proteomic signatures of social isolation and loneliness associated with morbidity and mortality. Nat Hum Behav (2025). https://doi.org/10.1038/s41562-024-02078-1