Trajectory classes of social activity and their effects on longitudinal changes in cognitive function among older adults.

OBJECTIVES This study aimed to identify the social activity trajectory by class and the effects on the cognitive function trajectory among older adults. METHODS Data from six waves of the 2006-2016 Korean Longitudinal Study of Aging were analyzed. This study included 3,002 participants aged ≥65 years. Latent class growth modeling was used to classify the respondents based on their engagement in social activity over 10 years. Latent growth modeling was used to examine the effect of their social activity trajectory by class to predict participants' cognitive function trajectory. RESULTS We identified four social activity trajectory classes: high-stable (7.8%), moderate-stable (50.3%), high-decreasing (2.9%), and low-decreasing (39.0%). Older adults with an age of 75 years or older, a low education level, instrumental activities of daily living limitations, and depressive symptoms were more likely to be in the low-decreasing social activity trajectory class. The respondents in the high-stable (B = 0.680, p < 0.001) and moderate-stable (B = 0.362, p < 0.001) classes showed a slower rate of cognitive decline compared with those in the low-decreasing class. DISCUSSION Community-based strategies need to be developed to encourage older adults to maintain their social activity engagement and ultimately prevent cognitive decline.