Can modifiable dementia risk factors help account for the predictive link between personality and midlife cognitive health? Evidence from a 17-year longitudinal study of Mexican-origin adults

INTRODUCTION: Prior research has established that dementia risk factors and personality traits separately predict cognition in mid-to-late life. The present research tests whether Lancet Commission dementia risk factors mediate the link between personality and midlife cognitive function. METHODS: We examined whether the latent levels and slopes of Big Five personality trajectories were associated with midlife cognitive function and ten modifiable dementia risk factors (e.g., hypertension, depression symptoms, sleep problems), using data from a 17-year longitudinal study of 1,106 Mexican-origin adults in the United States.RESULTS: All Big Five domains had prospective associations with multiple dementia risk factors and with cognitive impairment, cognitive function, and self-reported memory. Individuals higher in Extraversion, Agreeableness, Conscientiousness, and Openness had lower levels of dementia risk factors, lower likelihood of cognitive impairment, and better cognitive function. Individuals higher in Neuroticism generally showed the opposite pattern. Specific risk factors (depression, hearing loss, and hypertension) mediated the association between personality and some cognitive outcomes.DISCUSSION: By examining how dementia risk factors relate to personality traits and cognitive health outcomes, we clarify whether modifiable risk factors account for the personality–cognition link in Mexican-origin adults, an underrepresented population at greater risk of Alzheimer's disease and related dementias.