Reducing social isolation protects the brain in later life

Connecting Generations member Dr Jo Mhairi Hale from the University of St Andrews is the lead author of a newly published study which has found that reducing social isolation protects the brain in later life.

The study, published in The Journals of Gerontology, Series B: Psychological Sciences and Social Sciences, found a consistent pattern of higher social isolation causing faster cognitive decline whether or not people identify as lonely. Social isolation is objectively measured as, for example, sociability, membership in community organisations, and religious participation, whereas loneliness is a subjective report of how often people feel lonely. Whilst social isolation and loneliness are often thought of as associated, they appear to have independent effects on cognitive function. 

The  School of Geography and Sustainable Development at St Andrews, alongside researchers from the Max Planck Institute for Demographic Research in Germany and Emory University in the US, analysed data from the US Health and Retirement study, looking at 137,653 cognitive function tests taken between 2004 and 2018 by over 30,000 individuals. They found that reducing social isolation has a protective effect on cognitive function for all subpopulations, regardless of gender, race, ethnicity , and educational level, with only minor differences among social categories.  

There has been a great deal of interest in the health effects of social isolation and loneliness, especially focused on adolescents and older adults. Before Covid-19, about a quarter of older individuals (65 and over) identified as being socially isolated, spurring concerns about health implications. Likewise, loneliness has been recognised as a major public health issue in high-income countries, including the US, UK, Sweden, Australia, Germany and Japan. In the US, Alzheimer’s disease already afflicts an estimated 6.9 million people, with around 1 in every 11 of over 65s affected in the UK. With no known cure, prevention is all-important.  

Lead author of the paper, Dr Jo Hale from the University of St Andrews, said: “Around the holidays, many of us think a lot about how important it is to be surrounded by family and friends. From Pagan winter holidays to classic Christmas tales, we’re reminded that social engagement is good for our mental health.  This research shows that it’s also important for our cognitive health. As Alzheimer’s is a leading cause of death for older adults in the UK/US, constructing the scaffolding to allow for regular social interaction, especially for those who may not have family or friends nearby, should be a public health priority.”  

Read the full journal article: Disentangling social isolation, loneliness, and later-life cognitive function for older adults in the United States: Evidence from causal inference modeling

The study was also reported in the news articles:

Why going to your Christmas drinks tonight could help you later in life (The Independent)

Scientists unravel main cause of cognitive decline in landmark research tracking 30,000 Americans for decades (Daily Mail)

This story was originally published by the University of St Andrews: Reducing social isolation protects the brain in later life

Posted 19/12/2025 11:08