Causal mediation of the association between educational attainment and late-life cognitive function by trajectories of social participation

Abstract

Background

Education is a well-established predictor for late-life cognition. Moreover, social participation is associated with late-life cognition and could mediate the association between education and cognitive function. Yet, few studies have formally tested this question within a causal mediation framework.

Methods

We used data from the Taiwan Longitudinal Study in Aging. Participants were aged 50 or above and recruited in 1989 (n = 4,400), stratified by age group (aged 50–64 years versus 65 or above). We used sequence analysis and optimal matching techniques to define clustered patterns of social participation and work trajectories. We then used a four-way decomposition to identify causal mediation of the association between educational attainment and cognitive function by social participation. Cognitive function was measured by the Short Portable Mental Status Questionnaire.

Results

The mediating pathway through social participation accounted for 5% or less of the total relation of education on late-life cognitive function for both younger and older subgroups. The interaction between education and social participation accounted for 22% (middle/high school) and 34% (college+) of the total effect, contrasting with no formal education. We estimated that 36% (95% C.I. = 0.09, 0.69) of the educational disparity in late-life cognition among the younger cohort could be eliminated if the least educated group's social participation matched that of the college or above group. Social participation was not a significant mediator in the older subgroup.

Conclusion

To mitigate educational disparities in late-life cognitive function, further exploration of encouraging more active social participation or stable employment should be undertaken.