White matter lesions volume increased with lower frequency of social contact — A large-scale dementia cohort study by Kyushu University analyzed the association between social isolation and brain atrophy

Epidemiological studies have reported that social isolation increases the risk of dementia, but the effects of social isolation on brain structures, such as atrophy, have not been fully clarified. In response to this issue, a joint research group led by Professor Toshiharu Ninomiya and Lecturer Naoki Hirabayashi of the Graduate School of Medical Sciences at Kyushu University, along with Hirosaki University, Iwate Medical University, Kanazawa University, Keio University, Matsue Medical Center, Ehime University, Kumamoto University and, Tohoku University analyzed the association between frequency of social contact and brain volume using brain magnetic resonance imaging (MRI) and health examination data from 8,896 dementia-free people aged 65 years and older who participated in the 'Japan Prospective Studies Collaboration for Aging and Dementia (JPSC-AD)' study, a large-scale dementia cohort study aimed at promoting longevity in a healthy society.

Participants were asked, "How often do you interact with non-cohabiting relatives and friends (e.g., visits or phone calls)?" Based on the answers, frequency of contact was categorized into every day, several times a week, several times a month, and seldom. The results showed that total brain volume and cognitive function-related regional brain volumes (temporal lobe, occipital lobe, cingulum, hippocampus, and amygdala) significantly decreased and white matter lesions volume significantly increased with lower frequency of social contact. In addition, depressive symptoms appeared to partly mediate the association in community-dwelling older people without dementia and were involved in 15% to 29% of the observed associations.

Ninomiya commented: "Although this study is a snapshot in time and does not conclude that social isolation causes brain atrophy, several studies have shown that exposing older people to a socially stimulating group stops the decline in brain volume and improves thinking and memory, suggesting that interventions to improve social isolation may prevent the decline in brain volume and associated dementia." In the future, the research group will use the results of a prospective follow-up study to examine in detail the associations between social isolation, structural brain changes and the development of dementia. The article was published in the online edition of Neurology.

Journal Information
Publication: Neurology
Title: Association Between Frequency of Social Contact and Brain Atrophy in Community-Dwelling Older People Without Dementia: The JPSC-AD Study
DOI: 10.1212/WNL.0000000000207602