Supplementary Material for: Conscientiousness Is Associated with Lower Risk of Dementia among Black and White Older Adults

Background: While some personality traits may reduce risk of dementia, this is controversial and has not been studied as much among diverse populations. We examined associations between 2 traits – Conscientiousness and Openness to Experience – and risk of dementia among black and white older adults. Methods: We studied 875 older adults (ages 71–82, 47% black) without prevalent dementia from the Health, Aging and Body Composition study, who completed the NEO Five-Factor Inventory for Conscientiousness and Openness to Experience. Incident dementia over 8 years (mean = 6.9 years) was determined by hospital records, medications, or ≥1.5 SD race-specific decline on the Modified Mini-Mental State Examination. In adjusted models, we investigated associations between each trait and risk of dementia, including for race interactions. Results: Associations between personality traits and dementia risk did not differ by race (interactions: p > 0.7). Higher Conscientiousness was associated with lower dementia risk (adjusted HR per 1SD = 0.78; 95% CI 0.65–0.94). There was no association for Openness to Experience (adjusted HR per 1SD = 0.88; 95% CI 0.71–1.08). Conclusions: Higher Conscientiousness is associated with lower dementia risk, even among diverse populations. Higher Conscientiousness may be protective, or lower Conscientiousness may be an early symptom of neurodegenerative disease.