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)

Abstract

Background: Among older adults, poorer cognitive functioning has been associated with impairments in instrumental activities of daily living (IADLs). However, IADL impairments among older Hispanics/Latinos is poorly understood.

Objective: To characterize the relationships between cognition and risk for IADL impairment among diverse Hispanics/Latinos.

Methods: Participants included 6,292 community-dwelling adults from the Study of Latinos - Investigation of Neurocognitive Aging, an ancillary study of 45+ year-olds in the Hispanic Community Health Study/Study of Latinos. Cognitive data (learning, memory, executive functioning, processing speed, and a Global cognitive composite) were collected at Visit 1. IADL functioning was self-reported 7 years later, and treated as a categorical (i.e., risk) and continuous (i.e., degree) measures of impairment. Survey two-part models (mixture of logit and generalized linear model with Gaussian distribution) and ordered logistic regression tested the associations of cognitive performance (individual tests and composite z-score) with IADL impairment. Additionally, we investigated the moderating role of age, sex, and Hispanic/Latino background on the association between cognition and IADL impairment.

Results: Across all cognitive measures, poorer performance was associated with higher odds of IADL impairment 7 years later. Associations were generally stronger for the oldest group (70+ years) relative to the youngest group (50-59 years). Sex and Hispanic/Latino background did not modify the associations. Across the full sample, lower scores on learning, memory, and the Global cognitive composite were also associated with higher degree of IADL impairment.

Conclusion: Across diverse Hispanics/Latinos, cognitive health is an important predictor of everyday functioning 7 years later, especially in older adulthood.

Keywords: Activities of daily living; aging; cognition; hispanics; latinos; sex.

Figure 1.

Marginal IADL sum scores from two-part models examining associations between Visit 1 cognitive outcomes and IADL sum score. Crude (dark gray, solid line) models control for age and sex. Adjusted (light gray, dashed line) models control for age, sex, Center for Epidemiologic Studies Depression (CESD-10), time from Visit 1 to Visit 2 (days), education, and Field Center. B-SEVLT: Brief Spanish English Verbal Learning Test; WF: Word Fluency; DSS: Digit Symbol Subtest; SIS: Six-Item Screener; IADL: Instrumental activities of daily living.

Figure 2.

Ordered logistic regression marginal estimates with 95% confidence intervals by level of IADL impairment. Levels of impairment were categorized as “Good”/ No IADL disabilities (black circles): IADL sum score = 0; “Average” (gray squares): IADL sum score = 1–2; and “Poor” (blue diamonds): IADL sum score > 2. Models adjusted for age, sex, Center for Epidemiologic Studies Depression (CESD-10), time from Visit 1 to Visit 2 (days), education, and Field Center. B-SEVLT: Brief Spanish English Verbal Learning Test; WF: Word Fluency; DSS: Digit Symbol Subtest; SIS: Six-Item Screener; IADL: Instrumental activities of daily living.

Figure 3.

Age modifications in the associations between Visit 1 cognitive outcomes and IADL sum score. Age groups were categorized as 50–59 years (black circles); 60–69 years (gray squares); and 70+ years (blue diamonds). Models adjusted for sex, Center for Epidemiologic Studies Depression (CESD-10), time from Visit 1 to Visit 2 (days), education, and Field Center. B-SEVLT: Brief Spanish English Verbal Learning Test; WF: Word Fluency; DSS: Digit Symbol Subtest; SIS: Six-Item Screener; IADL: Instrumental activities of daily living