Cohort Differences in Cognitive Impairment and Cognitive Decline among Mexican-Americans Aged 75 and Older

Abstract

Research suggests the prevalence and incidence of cognitive impairment among older adults is decreasing. This analysis used data from nine waves (1993-2016) of the Hispanic Established Populations for the Epidemiologic Study of the Elderly to assess the cognitive status and cognitive decline for two cohorts of Mexican-Americans aged ≥75 in 1993/94 versus 2004/05. Logistic regression, joint longitudinal-survival models, and illness-death models for interval-censored data were used to examine cohort differences in the odds of prevalent cognitive impairment, trajectories of cognitive decline, and the risk for 10-year incident cognitive impairment, respectively. Results indicated that compared to the 1993/94 Cohort, the 2004/05 Cohort had higher odds for prevalent cognitive impairment (odds ratio: 2.51, 95% confidence interval [CI]: 1.92, 3.29), particularly among participants with <4 years of education (odds ratio:2.99 95% CI: 2.14, 4.18). Conversely, the 2004/05 Cohort exhibited significantly slower rates of cognitive decline (βˆ: 0.50, 95% CI: 0.39, 0.62) and had a significantly lower risk for incident cognitive impairment (hazard ratio: 0.75, 95% CI: 0.62, 0.91) compared to the 1993/94 Cohort. This analysis provides mixed results for cohort trends in the cognitive health of older Mexican-Americans. Continued research is needed to identify risk factors that contribute to these population-level trends.