Is Acculturation Associated with the Cognitive Performance of Older Hispanics?

Associations of Nativity and the Role of the Hispanic Paradox on the Cognitive Health of Older Latinos Living in the United States

Background

US-based Latinos have lower education and income combined with higher health risks than non-Latino whites, but often 'paradoxically' evidence better health-related outcomes. Less work has investigated this paradox for cognitive-related outcomes despite nativity diversity.

Objective

We evaluated cognitive aging within older Latinos of diverse nativity currently living in the US and participating in Rush Alzheimer's Disease Center studies.

Methods

Participants without baseline dementia, who completed annual neuropsychological assessments (in English or Spanish) were grouped by US-born (n = 117), Mexico-born (n = 173), and born in other Latin American regions (LAr-born = 128). Separate regression models examined associations between nativity and levels of (N = 418) or change in (n = 371; maximum follow-up ∼16 years) global and domain-specific cognition.

Results

Demographically-adjusted linear regression models indicated that foreign-born nativity was associated with lower levels of global cognition and select cognitive domains compared to US-born Latinos. No associations of nativity with cognitive decline emerged from demographically-adjusted mixed-effects models; however, Mexico-born nativity appeared associated with slower declines in working memory compared to other nativity groups (p-values ≥ 0.051). Mexico-born Latinos had relatively higher vascular burden and lower education levels than other nativity groups; however, this did not alter results.

Conclusions

Nativity differences in baseline cognition may be due, in part, to accumulated stressors related to immigration and acculturation experienced by foreign-born Latinos which may hasten meeting criteria for dementia later in life. In contrast, Mexico-born participants' slower working memory declines, taken in the context of other participant characteristics including vascular burden, suggests the Hispanic Paradox may relate to factors with the potential to affect cognition.

The Moderating Role of Race and Ethnicity in the Association Between Cognitive Performance and Functional Abilities in Later Life

This study examined ethnic/racial influences on the relationship of cognitive performance and functional abilities of 2,713 older individuals from the National Health and Nutrition Examination Survey (NHANES). Functional domains included activities of daily living (ADL), instrumental ADL, and leisure and social activities. In adjusted logistic regression models, low cognitive performance as assessed by the Digit Symbol Substitution Test was found significantly associated with functional limitation in each domain. However, moderation analysis revealed that being Hispanic and non-Hispanic Black may weaken this association demonstrating protective effects of underrepresented ethnic/racial status. Future studies should investigate perceived discrimination and resilience.

Relationships of Low Cognitive Performance and Sleep Disorder With Functional Disabilities Among Older Adults

Objectives

This study examined the relationships of low cognitive performance and sleep disorder with functional disabilities among older adults. Methods: NHANES 2011–2014 data on 3179 individuals [Mage=69.71] were analyzed. Functional domains included: activities of daily living (ADL), instrumental ADL (IADL) and leisure and social activities (LSA). Animal Fluency Test and the Digit Symbol Substitution Test assessed cognitive performance. Participants self-reported having physician-diagnosed sleep disorder. Results: Participants with both low cognitive performance and sleep disorder had 4- to 10-times greater odds for ADL, IADL, and LSA difficulties compared to the participants with no low cognitive performance/sleep disorder. Participants with only low cognitive performance and those with only sleep disorder were two to three times more likely to experience these difficulties. Discussion: Low cognitive performance and sleep disorder together or independently were associated with functional disabilities. Participants with both low cognitive performance and sleep disorder had higher odds of functional disabilities.

Association Between High Serum Tetrahydrofolate and Low Cognitive Functions in the United States: A Cross-Sectional Study

Background: The relationship between serum folate status and cognitive functions is still controversial. Objective: To evaluate the association between serum tetrahydrofolate and cognitive functions. Methods: A total of 3,132 participants (60–80 years old) from the 2011–2014 NHANES were included in this cross-sectional study. The primary outcome measure was cognitive function assessment, determined by the Consortium to Establish a Registry for Alzheimer’s Disease Word Learning Test (CERAD-WL), CERAD-Delayed Recall Test (CERAD-DR), Animal Fluency Test (AF), Digit Symbol Substitution Test (DSST), and global cognitive score. Generalized linear model (GLM), multivariate logistic regression models, weighted generalized additive models (GAM), and subgroup analyses were performed to evaluate the association between serum tetrahydrofolate and low cognitive functions. Results: In GLM, and the crude model, model 1, model 2 of multivariate logistic regression models, increased serum tetrahydrofolate was associated with reduced cognitive functions via AF, DSST, CERAD-WL, CERAD-DR, and global cognitive score (p <  0.05). In GAM, the inflection points were 1.1, 2.8, and 2.8 nmol/L tetrahydrofolate, determined by a two-piece wise linear regression model of AF, DSST, and global cognitive score, respectively. Also, in GAM, there were no non-linear relationship between serum tetrahydrofolate and low cognitive functions, as determined by CERAD-WL or CERAD-DR. The results of subgroup analyses found that serum tetrahydrofolate levels and reduced cognitive functions as determined by AF had significant interactions for age and body mass index. The association between high serum tetrahydrofolate level and reduced cognitive functions as determined using DSST, CERAD-WL, CERAD-DR, or global cognitive score had no interaction with the associations between cognition and gender, or age, or so on. Conclusion: High serum tetrahydrofolate level is associated with significantly reduced cognitive function.