The study followed 5,022 adults over the age of 65 from the National Health and Aging Trends Study—a longitudinal and nationally representative group of older adults in the U.S.—over the course of nine years (i.e., 2011 to 2020).
Within the group, approximately one in four older U.S. adults faced social isolation—i.e., they had few social relationships and infrequent contact with others. the results showed that social isolation was associated with a 28% higher risk of developing dementia (25.9% of the socially isolated group had probably dementia, compared to 19.6% of the non-isolated group).
While this statistic seems high, researchers warn that the association between dementia and social isolation may be underestimated, as older adults living in nursing homes and residential care facilities (in which dementia and social isolation are highly prevalent) were not included in this study.
While the findings did not vary by race in this study, scientists conclude that more research is needed to determine the specific dementia-related implications of social isolation on different racial and ethnic groups, as a higher prevalence of dementia has been found in African American, Hispanic, American Indian, and Alaska Native older adults compared to White older adults. With the growing diversity of the aging population, accounting for racial and ethnic disparities within the design of future longitudinal population studies is imperative.