An 11-Fold Higher Risk of Incident Mild Cognitive Impairment With Hispanic Ethnicity and Baseline Neuropsychiatric Symptoms.

Objective: Neuropsychiatric symptoms (NPSs) have been linked to cognitive decline. This study explored ethnic differences and the effects of baseline NPSs on incident mild cognitive impairment (MCI) among 386 Hispanic and non-Hispanic participants from the Texas Harris Alzheimer's Research Study.

Methods: Data on NPSs from the Neuropsychiatric Inventory Questionnaire were available for all participants. Cox proportional hazards regression models were used to estimate the effect of ≥1 NPS at baseline and Hispanic ethnicity on incident MCI over a 7-year follow-up period.

Results: NPSs at baseline were associated with incident MCI for Hispanic participants but not non-Hispanic participants. Being Hispanic with at least one NPS at baseline had an 11-times higher risk of incident MCI.

Conclusions: The Hispanic participants converted to MCI to a greater extent than the non-Hispanic participants. Only depressive symptoms increased the risk of MCI among non-Hispanics. Being of Hispanic ethnicity and having NPSs appeared to jointly increase the risk of progressing to MCI. To better understand the Alzheimer's disease continuum, further studies should explore other cultural, genetic, and medical risk factors influencing disease progression. Our findings strongly suggest the need to incorporate NPSs as outcomes of disease progression in future clinical trials involving Hispanic participants.