Social isolation is directly associated with later dementia, study says

According to a University of Warwick study, social isolation is directly related with alterations in brain areas associated with memory, making it a definite risk factor for dementia.

Researchers from the Universities of Warwick, Cambridge, and Fudan University utilised neuroimaging data from over 30,000 adults in the UK Biobank data set to study how social isolation and loneliness were associated to eventual dementia. Individuals who are socially isolated have reduced grey matter volumes in brain areas involved in memory and learning.

The results of the study are published online today (June 8, 2022) in Neurology, the medical journal of the American Academy of Neurology, in a paper entitled “Associations of social isolation and loneliness with later dementia” by Shen, Rolls, Cheng, Kang, Dong, Xie, Zhao, Sahakian and Feng.

The researchers employed modelling tools to explore the relative relationships of social isolation and loneliness with incident all-cause dementia using data from the UK Biobank, an unusually large longitudinal cohort. After controlling for other risk variables (such as socioeconomic status, chronic disease, lifestyle, depression, and APOE genotype), socially isolated people were shown to have a 26% greater chance of acquiring dementia.

Loneliness was also linked to later dementia, however the link was lost after controlling for depression, which accounted for 75% of the interaction between loneliness and dementia. As a result, objective social isolation, as opposed to subjective loneliness, is an independent risk factor for later dementia. Further subgroup analysis revealed that the impact was strongest in people over the age of 60.

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.”

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“Both have risks to health but, using the extensive multi-modal data set from the UK Biocomputational scbank, and working in a multidisciplinary way linking iences 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.”

Professor Jianfeng Feng, from the University of Warwick Department of Computer Science, said: “We highlight the importance of an environmental method of reducing risk of dementia in older adults through ensuring that they are not socially isolated. During any future pandemic lockdowns, it is important that individuals, especially older adults, do not experience social isolation.”

Professor Barbara J Sahakian, of the University of Cambridge Department of Psychiatry, said: “Now that we know the risk to brain health and dementia of social isolation, it is important that the government and communities take action to ensure that older individuals have communication and interactions with others on a regular basis.”

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