Late‐life social activity and subsequent risk of dementia and mild cognitive impairment

Abstract

AbstractBackgroundPrevious research reported associations between more social engagement and better cognitive health. Social engagement is a multidimensional construct encompassing interrelated but distinct domains such as social activity, social network size, perceived social support, and loneliness. These domains are not equally amenable to interventions. We therefore focused on late‐life social activity, as a potentially modifiable facet of social engagement, and examined its relation to risks of dementia and MCI, independent of other aspects of social engagement, lifestyle, and health.MethodIn the Rush Memory and Aging Project (MAP), 1923 older adults without dementia at baseline were followed longitudinally, with annual clinical evaluation of dementia and MCI. The frequency of participation in six common social activities was assessed by a validated scale at baseline (mean = 2.6, range: 1‐4.3), as were size of social network, perceived social support, and perceived loneliness. A clinical diagnosis of MCI or dementia was rendered annually based on cognitive tests and diagnostic classification by a clinician. We used Cox proportional hazard models to quantify associations between social activity score and incident dementia or MCI. Primary models controlled for demographics; additional models included covariates for health, other social engagement indicators, and income. In secondary analyses, to consider reverse causality, we excluded participants who developed MCI or dementia within two years after baseline.ResultDuring a mean follow‐up of 6.7 (std = 4.7) years, 545 (28%) participants developed dementia, and 695 (49% of those without MCI at baseline) developed MCI. Each one‐unit increment in social activity score was associated with a 37% reduction in dementia risk [HR = 0.63, 95% CI: 0.53‐0.74] after adjusting for age, sex, education, race/ethnicity, and marital status (Figure 1A). Social activity was also related to a lower risk of MCI [HR = 0.77, 95% CI: 0.66‐0.89] (Figure 1B). Results were not meaningfully different after adjusting for vascular disease burden, BMI, ADL disability, physical activity, depressive symtoms, social network size, social support, social isolation, and income. Excluding participants who developed MCI or dementia soon after baseline did not change the patterns.ConclusionKeeping socially active at older age is related to lower dementia risk, possibly informing strategies for developing preventive interventions.