Prevalence of Instrumental Activities of Daily Living (IADL) Difficulties and Associated Cognitive Predictors Across Racial/Ethnic Groups: Findings from the KHANDLE Study.

Objective Cognitive functioning is associated with instrumental activities 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. Methods Participants included 455 non-Hispanic Whites, 395 Blacks, 370 Asians, and 296 Latinos age ≥65 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 IADL 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.