Social isolation linked to less brain matter, higher risk for dementia

Social isolation has become a topic of concern for people of all ages during the coronavirus pandemic. Now, a new study reveals older adults experiencing social isolation are more likely to have less brain matter in areas tied to cognitive ability. In turn, this puts them at greater risk for developing dementia.

“Social isolation is a serious yet underrecognized public health problem that is often associated with old age,” explains study author Jianfeng Feng, PhD, of Fudan University, in a media release. “In the context of the COVID-19 pandemic, social isolation, or the state of being cut off from social networks, has intensified. It’s more important than ever to identify people who are socially isolated and provide resources to help them make connections in their community.”

To reach these findings, study authors looked more than 460,000 older adults in the United Kingdom, measuring each person’s levels of social isolation, loneliness, and cognitive ability. Importantly, all of the participants had an average age of 57 and researchers followed them for nearly 12 years prior to the COVID-19 pandemic.

During that time, nine percent (41,886) reported being socially isolated and six percent (29,036) felt lonely. Specifically, study authors asked three questions to measure social isolation: Do the participants live alone? Do friends or family visit them at least once a month? Finally, do they participate in social activities with others at least once a week. Researchers considered anyone answering no to at least two questions to be suffering from social isolation.

Along with the survey data, researchers also collected physical and biological measurements, including MRI data, and had the group complete thinking and memory tests to assess cognitive function.

Does isolation actually make the brain smaller?

Overall, 4,998 people developed dementia during the study. When you break that number down further, however, 649 socially isolated individuals developed dementia (1.55%), compared to 4,349 out of 420,733 people not experiencing social isolation (1.03%).

Moreover, socially isolated participants had lower volumes of gray matter in brain regions with a connection to both thinking and learning. This connection remained steady after researchers accounted for differences in age, sex, socioeconomic status, alcohol and smoking habits, and levels of depression and loneliness.

Statistically, people experiencing more social isolation were 26 percent more likely to develop dementia than others with no history of social isolation. Again, these results come from a period before the worldwide lockdowns during COVID.

The team notes that they did not find the same link between dementia onset and loneliness — which previous studies say is a very different condition than social isolation.

“People who reported high levels of social isolation had significant differences in brain volume, also associated with cognition and dementia,” Feng concludes. “Given the findings of this study, social isolation may be an early indicator of an increased risk of dementia.”

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

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