A new study published in the journal Neurology has shown that people who are socially isolated are at a higher risk of developing dementia.¹

For this study, researchers analyzed data from the UK Biobank cohort with the objective of examining the association of social isolation and loneliness with new onset of dementia. At the time of their enrollment, the average age was 57 years. The participants undertook thinking and memory tests for cognitive assessment and were enquired about their social contact via three questions: whether they lived alone or with others; did they take part in social activities at least once in a week and did they visit their family or friends at least once in a month. At least two negative responses were considered social isolation. In addition to demographic, biological and behavioral data, the MRI scans of the participants were also studied. The participants were followed for 12 years before the Covid-19 pandemic.

A total of 462,619 were examined and out of these, 41,886 (9%) reported social isolation, while 29,036 (6%) reported loneliness. During the course of the study, overall, 4998 participants developed incident dementia due to any cause. Among the 41,886 people with social isolation, 649 (1.55%) developed dementia vs 4349 (1.03%) of the remaining who did not report social isolation. The risk of developing dementia was 1.26-times higher in those who reported social isolation compared to those with no social isolation. This association was independent of other risk factors including depression and loneliness. Among those who reported feeling lonely, the adjusted hazard ratio for dementia was 1.04 and was largely linked to depression.

MRI data was available for 32,263 participants with a mean age of 63.5 years. The gray matter volumes in temporal, frontal and hippocampal regions were lower in the socially isolated individuals after adjusting for demographic and socioeconomic data including alcohol intake and smoking, and other conditions like depression and loneliness.

Social isolation and loneliness are increasing in society, particularly among older adults. The pandemic has only aggravated it further. They have an adverse impact on health and quality of life. Social exclusion has been identified by the WHO as one among the 10 key social determinants of health, which have been rightly called as “causes of causes”. “Social isolation is the objective state of having a small network of kin and non-kin relationships and thus few or infrequent interactions with others”. But “socially isolated people are not necessarily lonely”, says the WHO.²

By demonstrating an association between social isolation and dementia, which was independent of loneliness and other variables, researchers have identified social isolation as “an early indicator of an increased risk of dementia”. Loneliness was also examined for any likely link with dementia, but the correlation between the two was not as robust as it was for social isolation. Participants who were socially isolated had lower gray matter volumes in the areas of the brain associated with cognitive functions. Hence, socially isolated people must be identified and efforts made to connect them to the local community and encourage social interaction.

References

1. Chun Shen, et al. Associations of social isolation and loneliness with later dementia. Neurology. June 2022, 10.1212/WNL.0000000000200583; DOI: 10.1212/WNL.0000000000200583.
2. Social isolation and loneliness among older people: advocacy brief. Geneva: World Health Organization; 2021. Licence: CC BY-NC-SA 3.0 IGO