Cognition and Daily Functioning: Results from the Hispanic Community Health Study/Study of Latinos (SOL) and Study of Latinos-Investigation of Neurocognitive Aging (SOL-INCA)

Prevalence of Instrumental Activities of Daily Living Difficulties and Associated Cognitive Predictors Across Racial/Ethnic Groups: Findings From the KHANDLE Study

OBJECTIVE

Cognitive functioning is associated with instrumental activity of daily living (IADL) performance among older adults. The present study examines potential differences in the prevalence of IADL difficulty and association with cognition across diverse groups.

METHOD

Participants included 455 non-Hispanic Whites, 395 Blacks, 370 Asians, and 296 Latinos aged 65 years and older without a current dementia diagnosis from the Kaiser Healthy Aging and Diverse Life Experience cohort. Participants' self-reported IADL functioning and cognition was measured across episodic memory and executive functioning.

RESULTS

Older age, male gender, and being Black were associated with more IADL difficulties. Executive functioning showed a stronger association with IADLs than memory, and it was independent of health status, whereas memory was not. In joint models including both cognitive domains, executive functioning remained a significant predictor of IADL difficulty, but memory did not. Results for both cognitive domains were attenuated with self-rated health added to the joint model. These relationships did not significantly differ across racial/ethnic groups.

CONCLUSIONS

Our study supports previous work suggesting that Black older adults are at increased risk for IADL disability. This is the first study we are aware of that examined the association between specific cognitive domains and IADL performance across multiple racial/ethnic groups. Findings indicate that cognitive functioning has similar associations with self-reported IADL disability across diverse groups, and that executive functioning plays a particularly important role in IADL disability among older adults without dementia; however, health status largely attenuates the relationship between IADL difficulty and cognition.

Race/Ethnic Differences, Skin Tone, and Memory Among Older Latinos in the United States

OBJECTIVES

U.S. Latino populations are diverse. Research on racial identity, skin tone, and Latino health is imperative for understanding and combating racism and colorism. We examined differences in memory performance: among non-Latinos and Latinos who identified as Black, other, and White in the United States and then among Puerto Ricans in Boston whose skin tones ranged from dark, medium, light to "white."

METHODS

We used 2010 Health and Retirement Study and 2004 Boston Puerto Rican Health Survey data, respectively, to examine racial and color differences in memory performance among 50 and older adults in the United States and Puerto Rican older adults in Boston. We applied ordinary least squares regression to immediate and delayed word recall test scores and adjusted for education, health conditions, and health behaviors.

RESULTS

In adjusted models, White non-Latinos had better memory performance than White Latinos. Black Latinos, other Latinos, and Black non-Latinos had lower delayed word recall scores than White Latinos. Black Latinos and Black non-Latinos had similar scores. Intra-Latino racial disparities endured despite the inclusion of education and other covariates. Among Puerto Ricans in Boston, medium-toned individuals had higher scores than "white"-toned individuals.

DISCUSSION

Findings support the importance of examining self-identified race and skin tone in Latino aging research. Further investigation is needed to understand the stubborn intra-Latino racial disparities in memory performance and surprising adverse cognitive performance among "white"-toned relative to darker-toned Puerto Ricans in Boston.

The mediating role of cognition in the relationship between sleep duration and instrumental activities of daily living disability among middle-aged and older Chinese

OBJECTIVE

To explore the effect of sleep duration at baseline on the incident IADL disability among middle-aged and older Chinese, and test whether cognition mediates this causality.

METHODS

Data were collected from wave 1 (2011-2012) to wave 3 (2015-2016) of the China Health and Retirement Longitudinal Study (CHARLS). Sleep duration was self-reported at baseline. Cognitive function, including episodic memory and mental intactness were measured via a questionnaire. IADL was assessed at baseline and follow-up. Baron and Kenny's causal steps and Karlson/Holm/Breen (KHB) method were conducted to examine the mediating effect.

RESULTS

A total of 10,328 participants free of IADL disability at baseline were included in this study. Over 4 years of follow-up, 17.1% of participants developed IADL disability. Compared to 7-8 h sleep duration, both short sleep (OR=1.460; 95% CI: 1.261-1.690 for sleeping ≤5 h; OR= 1.189; 95% CI: 1.011-1.400 for sleeping 5-7 h) and long sleep (OR=1.703; 95% CI: 1.269-2.286 for sleeping >9 h) were linked with incident IADL disability. KHB method identified significant mediating effect of cognition on the relationship between extreme sleep durations (≤5 h or >9 h) and IADL disability and the proportional mediation through cognition was 21.32% and 21.06% for sleeping ≤5 h and >9 h, respectively.

CONCLUSION

Both short (sleeping ≤5 h) and long sleep duration (sleeping >9 h) predicted incident IADL disability. Cognition partially mediated the effect of extreme sleep durations on IADL disability.

Central Obesity, Cardiometabolic Risk, and Cognitive Change in the Study of Latinos - Investigation of Neurocognitive Aging

BACKGROUND

The relationships between obesity and cognitive decline in aging are mixed and understudied among Hispanics/Latinos.

OBJECTIVE

To understand associations between central obesity, cognitive aging, and the role of concomitant cardiometabolic abnormalities among Hispanics/Latinos.

METHODS

Participants included 6,377 diverse Hispanics/Latinos enrolled in the Hispanic Community Health Study/Study of Latinos (HCHS/SOL) and SOL-Investigation for Neurocognitive Aging (SOL-INCA). Participants were 45 years and older at the first cognitive testing session (Visit 1). Cognitive outcomes (z-score units) included global composite and domain specific (learning, memory, executive functioning, processing speed) measures at a second visit (SOL-INCA, on average, 7 years later), and 7-year change. We used survey linear regression to examine associations between central obesity (waist circumference≥88 cm and≥102 cm for women and men, respectively) and cognition. We also tested whether the relationships between obesity and cognition differed by cardiometabolic status (indication of/treatment for 2 + of the following: high triglycerides, hypertension, hyperglycemia, low high-density lipoprotein cholesterol).

RESULTS

Central obesity was largely unassociated with cognitive outcomes, adjusting for covariates. However, among individuals with central obesity, cardiometabolic abnormality was linked to poorer cognitive function at SOL-INCA (ΔGlobalCognition =-0.165, p < 0.001) and to more pronounced cognitive declines over the average 7 years (ΔGlobalCognition = -0.109, p < 0.05); this was consistent across cognitive domains.

CONCLUSION

Central obesity alone was not associated with cognitive function. However, presence of both central obesity and cardiometabolic abnormalities was robustly predictive of cognition and 7-year cognitive declines, suggesting that in combination these factors may alter the cognitive trajectories of middle-aged and older Hispanics/Latinos.