The participants were 65 or older, and were asked to complete an annual two-hour, in-person interview to assess their cognitive function, health status and overall well-being.
At the beginning of the study, 23 percent of the subjects were socially isolated and showed no signs of the brain condition.
However, 21 percent of the total sample had developed dementia at the end of the study, allowing researchers to conclude that the risk is higher in socially isolated people.
Alison Huang, senior research associate at the Johns Hopkins Bloomberg School of Public Health, said: “One possible explanation is that having fewer opportunities to socialise with others decreases cognitive engagement as well, potentially contributing to increased risk of dementia.”
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