Social isolation identified as dementia risk factor

New research shows changes in the brain structures associated with memory and cognitive function are directly linked to social isolation, making it a clear risk factor for dementia.

 Researchers at the University of Warwick, University of Cambridge and Fudan University used neuroimaging data from more than 30,000 participants in the UK, finding socially isolated individuals have lower gray matter volumes of brain regions involved in memory and learning.

After adjusting for various risk factors – including socio-economic factors, chronic illness, lifestyle, depression and APOE genotype – socially isolated individuals were shown to have a 26% increased likelihood of developing dementia.

Loneliness was also associated with later dementia, but that association was not significant after adjusting for depression, which explained 75% of the relationship between loneliness and dementia. Therefore, relative to the subjective feeling of loneliness, objective social isolation is an independent risk factor for later dementia.

Professor Edmund Rolls, neuroscientist from the University of Warwick Department of Computer Science, said: ‘There is a difference between social isolation, which is an objective state of low social connections, and loneliness, which is subjectively perceived social isolation.

‘Both have risks to health but, using the extensive multi-modal data set from the UK Biobank, and working in a multidisciplinary way linking computational sciences and neuroscience, we have been able to show that it is social isolation, rather than the feeling of loneliness, which is an independent risk factor for later dementia. This means it can be used as a predictor or biomarker for dementia in the UK.

‘With the growing prevalence of social isolation and loneliness over the past decades, this has been a serious yet underappreciated public health problem. Now, in the shadow of the COVID-19 pandemic there are implications for social relationship interventions and care – particularly in the older population.’

The results of the study were published in Neurology, the medical journal of the American Academy of Neurology.

Photo by Jeremy Wong