Childhood book availability helps to preserve cognitive function in older adults with low education: Results from the NEIGE study.

OBJECTIVES: It is well-known that low educational attainment is associated with cognitive function decline in older age. Childhood book availability may help to preserve cognitive function in older adults with low education. The study objective was to examine the association between childhood book availability and cognitive function among older adults with low educational attainment, and to investigate the mediating effect of the volume of reading-related brain regions (e.g., superior temporal cortex).

METHODS: A cross-sectional study of community-dwelling older Japanese adults aged 65-84 years was conducted (n=474). Cognitive function was assessed using the Mini-Mental State Examination (MMSE). Childhood book availability was assessed using a retrospective questionnaire. Brain region volume was measured using magnetic resonance imaging. Multivariate regression modeling and structural equation modeling were used for analysis.

RESULTS: Both high educational attainment and childhood book availability were independently associated with high MMSE score. Stratification of educational level showed that childhood book availability was positively associated with MMSE score among participants with low educational attainment (coefficient=1.48, 95% confidence interval (CI): 0.31 to 2.66), but not among those with moderate or high educational attainment (coefficient=-0.01, 95% CI: -1.44 to 1.42 and -1.21, 95% CI: -3.85 to 1.42, respectively). Among participants with low educational attainment, left superior temporal cortex volume mediated the association between childhood book availability and MMSE score.

DISCUSSION: The availability of books in childhood helps to preserve cognitive function in older adults with low education via left superior temporal cortex volume. Further research is needed to replicate these findings.