Researchers from China and the UK have found that social isolation, but not loneliness, is linked to lower brain volume in regions associated with cognition and higher dementia risk. The findings were published in the journal Neurology today (Wednesday 8 June).
Researchers looked at data from a large cohort of people across the United Kingdom with an average age of 57. These people were followed for nearly 12 years before the COVID-19 pandemic.
Participants filled out surveys about their social contact. They also did MRI (magnetic resonance imaging) brain scans and took thinking and memory tests.
Analysing the data collected, the researchers looked at the link between brain volume and social isolation, taking into account other factors such as age, sex and socioeconomic status.
What did they find?
The researchers found that people who are socially isolated had lower brain volume in regions associated with learning and thinking. These brain regions are typically among the first to be affected by Alzheimer’s, the most common cause of dementia.
The data shows that people who were socially isolated were 26% more likely to develop dementia compared to those who are not.
On the other hand, researchers found that loneliness – the internal feeling of being isolated from others – is not linked to an increased risk of developing dementia.
Dr Sara Imarisio, Head of Research at Alzheimer’s Research UK, said:
“Social isolation is a serious public health problem that is often associated with old age. This issue has worsened during the COVID-19 pandemic as more people were cut off from their usual social networks.
“Dementia risk depends on many factors. Social isolation and loneliness have been suggested to increase the risk of dementia.
“Researchers from this study were able to distinguish the effects of social isolation from loneliness on the brain and dementia. They observed that people who were socially isolated were more likely to develop dementia, and that loneliness was not associated to an increased risk of developing dementia. This finding may inform future approaches to reduce risk of dementia in older people living isolated lives.
“The group of participants studied had fewer health conditions and were less likely to live alone compared to the general population, so we can’t be certain how relevant these findings are to the country as a whole. We will need further studies that are more representative of the wider population to validate the conclusions of this research.
“We do know that it’s never too early or too late in life to take steps to reduce our risk of dementia and improve our brain health. Apart from staying socially active, there are many other ways to help keep our brains healthy as we age. These include being physical and mentally active, not smoking, only drinking in moderation, eating a balanced diet, and keeping cholesterol and blood pressure levels in check.”