Research from the Rush Memory and Aging Project reveals that older adults who engage in more social activities develop dementia up to five years later than those who are less socially active, highlighting the power of social connections in brain health.
Study: Late-life social activity and subsequent risk of dementia and mild cognitive impairment. Image Credit: bbernard/Shutterstock.com
In a recent study published in Alzheimer’s & Dementia, researchers investigated the relationship of social activity with the risk of mild cognitive impairment (MCI) and dementia.
Background
An estimated 50 million adults are affected by dementia worldwide, with annual global spending on dementia being $263 billion.
As such, strategies to delay or prevent dementia are paramount. Some evidence suggests that social engagement is linked to reduced dementia risk and less cognitive decline, and thus, could be a potential avenue to prevent dementia.
Social engagement is a multi-dimensional construct comprising distinct but interrelated domains, such as subjective psychosocial experience (loneliness), functional aspects (social support), and structural elements (marital status, social activity).
Social activity has been a robust and consistent risk factor for cognitive health, and it could be more amenable to population-level intervention than others.
About the study
In the present study, researchers examined the associations between social activity and incident MCI and dementia. Participants from the Rush Memory and Aging Project, a longitudinal clinical-pathological study established in 1997, were analyzed.
They were recruited in the Chicago metropolitan area, and so far, around 2,300 older adults have completed baseline evaluation.
Social activity levels were estimated as participation frequency in six common social activities. Subjects rated how often they engaged in the following activities in the past year: 1) group participation, 2) going to sporting events, restaurants, or off-track betting, 3) visiting friends or relatives, 4) attending religious services, 5) going on day or overnight trips, and 6) doing unpaid volunteer or community work.
Subjects underwent a clinical diagnosis procedure at annual evaluations. A battery of 21 cognitive tests was scored.
A neuropsychologist offered clinical judgment about the presence of cognitive impairment based on the test score. Subsequently, a clinician made a diagnostic classification of dementia after reviewing cognitive testing, medical history, and neurological examination.
Participants were classified to have MCI if they had a neuropsychologist-ascertained impairment that did not meet the dementia diagnostic criteria. Subjects without dementia or MCI were classified as having no cognitive impairment.
The associations between social activity levels and time to incident MCI or dementia were examined using multivariable Cox proportional hazards models. Furthermore, age at dementia/MCI diagnosis was estimated across social activity levels.
Findings
Overall, 1,923 participants, with an average age of 80.4 years, were included for the analyses. They were followed up for a mean of 6.7 years, during which 36% and 28% developed MCI and dementia, respectively.
The mean social activity score was 2.6, reflecting a participation frequency of several times a month. Participants had about seven social contacts they had seen at least once a month.
A unit increase in social activity score was associated with a 38% reduced risk of dementia after adjusting for sex, age, education, marital status, and race/ethnicity.
To assess whether social activity was independently associated with incident dementia, other variables of social engagement, e.g., loneliness, social network size, and social support, were included in the model.
The inclusion of additional variables yielded comparable associations between social activity and dementia. Moreover, there was a significant association between loneliness and incident dementia, with a unit increment in loneliness being associated with a 40% increased dementia risk. Social support and network size were unrelated to incident dementia.
The least socially active participants had a significantly lower probability of remaining dementia-free than the most socially active.
Further, social activity was strongly associated with the age at dementia diagnosis; the predicted average age at dementia onset was 87.7 years for the least socially active and 92.2 years for the most socially active.
In addition, social activity was associated with a lower risk of MCI after adjusting for sex, education, marital status, ethnicity/race, and age.
A unit increment in social activity score was associated with a 21% reduced MCI risk. Further, the predicted average age at MCI onset was 74.2 and 79.1 years for the least and most socially active participants, respectively.
Conclusions
In sum, the findings indicate that greater social activity levels were associated with a five-year older age at the onset of dementia relative to the least socially active participants.
Similarly, there was a five-year difference in the age at the onset of MCI between the most and least socially active individuals. These results underscore the value of social activity as a possible community-level intervention to reduce dementia.
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