Cognitive impairment as a strong predictor of incident disability in specific ADL-IADL tasks among community-dwelling elders: the Azuchi Study.
OBJECTIVE
We examined differential effects of cognitive impairment on each of the activities of daily living (ADL) and instrumental activities of daily living (IADL) tasks.


METHODS
In a 3-year follow-up of community-dwelling elderly persons in Azuchi, Japan, we assessed cognition by using the Hasegawa Dementia Scale. We examined (a) the cross-sectional association between cognitive impairment and functional disability in each ADL-IADL item; (b) cognitive impairment as a risk factor for incident disability in each ADL-IADL item, through logistic regression models; and (c) probabilities of incident loss of ADL-IADL abilities or death in 3 years, using multinomial logistic regression models. We also calculated the population attributable risk (PAR%) of cognitive impairment on incident loss of task-specific ADL-IADL abilities.


RESULTS
Cross-sectionally, the severity of cognitive impairment was associated with disability in each ADL-IADL task, with larger effects shown for ADL items. Longitudinally, minimally or mildly cognitively impaired individuals had a significantly higher risk of losing functional abilities compared with those with intact cognition. The PAR% indicated that cognitive impairment accounts for 11% to 36% of incident disability in ADL-IADL tasks, with the highest PAR% shown for the ability to feed oneself.


CONCLUSIONS
Cognitively impaired subjects are heterogeneous; the severity of cognitive impairment has a different impact on incident loss of task-specific ADL-IADL abilities, and comorbidities could affect disabilities differently. Consideration of these heterogeneities will enrich future studies on the impact of cognitive impairment on ADL-IADL abilities.
Dodge
Hiroko H
HH
Department of Epidemiology, University of Pittsburgh, Pittsburgh, PA 15261, USA. Dodge@edc.pitt.edu
Kadowaki
Takashi
T
Hayakawa
Takehito
T
Yamakawa
Masanobu
M
Sekikawa
Akira
A
Ueshima
Hirotugu
H
D000203:Activities of Daily Living; D000368:Aged; D000369:Aged, 80 and over; D017028:Caregivers; D003072:Cognition Disorders / Q000175:diagnosis* / Q000503:physiopathology; D006233:Persons with Disabilities; D005260:Female; D006801:Humans; D007564:Japan; D016015:Logistic Models; D008297:Male