Cognitive impairment as a strong predictor of incident disability in specific ADL-IADL tasks among community-dwelling elders: The Azuchi study

Hiroko Dodge, Takashi Kadowaki, Takehito Hayakawa, Masanobu Yamakawa, Akira Sekikawa, Hirotugu Ueshima

Research output: Contribution to journalArticle

112 Scopus citations


Purpose: We examined differential effects of cognitive impairment on each of the activities of daily living (ADL) and instrumental activities of daily living (IADL) tasks. Design and 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. Implications: 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.

Original languageEnglish (US)
Pages (from-to)222-230
Number of pages9
Issue number2
Publication statusPublished - Apr 2005
Externally publishedYes



  • ADL
  • Caregiving needs
  • Hasegawa Dementia Scale
  • IADL
  • Population attributable risk

ASJC Scopus subject areas

  • Aging

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