Personality and global cognitive decline in Japanese community-dwelling elderly people: A 10-year longitudinal study

OBJECTIVES: To examine the longitudinal associations between the big five personality and changes in global cognitive function among community-dwelling elderly people involved in the National Institute for Longevity Sciences - Longitudinal Study of Aging. METHODS: The participants were 594 individuals (age range 60-81years) and followed for 10years and tested six times. Personality was assessed by the Japanese version of NEO five factor inventory at baseline. Cognitive function was assessed by the Japanese version of Mini Mental State Examination (MMSE) at all visits. For participants with a baseline MMSE score≥28, logistic generalized estimating equation models estimated the odds ratio (OR) and 95% confidence interval (CI) for MMSE score≤27 at each follow-up visit, according to a 1-SD increase of the baseline personality score. Post hoc analyses were performed for mild cognitive deficits, baseline MMSE score≥24 and ≤27, to estimate the OR and CI for MMSE score≤23. RESULTS: The adjusted OR for MMSE score≤27 was 0.78 (95% CI, 0.69-0.88), with a 1-SD increase in Openness to Experience score. In post hoc analyses, the adjusted OR for MMSE score≤23 was 0.50 (95% CI, 0.35-0.72) with a 1-SD increase in Conscientiousness score. Relationships between other personality traits and the decline in MMSE score were not significant. CONCLUSIONS: Higher Openness to Experience was associated with a reduction in risk for cognitive decline in community-dwelling older adults. Higher Conscientiousness might also predict lower risk for severe cognitive decline, especially for individuals with mild cognitive deficits.