A longitudinal study of cognitive trajectories in Mexican Americans age 75 and older.

OBJECTIVE: To identify distinct trajectories for global cognition, memory, and non-memory domains among Mexican American adults 75 years of age and older.

METHODS: The final sample included 1336 participants of the Hispanic Established Population for the Epidemiologic Study of the Elderly observed during four Waves from 2004-2005 to 2012-2013. Latent class growth curve models were used to identify distinct trajectories for global cognition, memory, and non-memory.

RESULTS: Three trajectory classes were identified for global cognition, memory, and non-memory domains. Nearly 31% of the final sample maintained high global cognition (persistent high), 52.6% experienced slight decline (decline but high), and 15% experienced severe decline in global cognition (decline to low). Over 95% of participants classified in the decline to low trajectory for global cognition were also classified as decline to low for memory and non-memory. This high level of consistency for memory and non-memory domains was observed for the decline but high (97.0%) and persistent high (93.7%) trajectory classes.

CONCLUSIONS: These results indicate that the majority of Mexican American older adults will experience varying degrees of cognitive decline. However, a substantial proportion of older Mexican Americans are able to maintain high cognitive functioning into advanced age despite the high prevalence of risk factors for cognitive decline in this population. Copyright © 2016 John Wiley & Sons, Ltd.