Cognitive functioning and walking speed in older adults as predictors of limitations in self-reported instrumental activity of daily living: prospective findings from the Obu Study of Health Promotion for the Elderly.

Hyuma Makizako,Takehiko Doi,Kota Tsutsumimoto,Sangyoon Lee,Sho Nakakubo,Seongryu Bae,Kenji Harada,Ryo Hotta,Takao Suzuki,Sungchul Lee,Hiroyuki Shimada,Kazuhiro Harada

doi:10.3390/ijerph120303002

Abstract

Our aim was to determine whether baseline measures of cognitive functioning, walking speed, and depressive status are independent predictors of limitations in instrumental activities of daily living (IADL) in older adults. The cross-sectional study involved 1329 community-dwelling adults, aged 75 years or older. At baseline, the Mini-Mental State Examination (MMSE), Symbol Digit Substitution Test (SDST), Geriatric Depressive Scale (GDS), and a word list memory task were completed, and self-reported IADLs and walking speed were recorded. The longitudinal study involved 948 participants without baseline IADL limitation, which was assessed at baseline and 15-month follow up, using the three Kihon Checklist subitems. In cross-sectional analyses, participants with IADL limitation demonstrated greater GDS scores, slower walking speeds, and lower MMSE, word list memory task, and SDST (only for women) scores relative to those without IADL limitation. In the longitudinal analyses, baseline walking speed (men: OR 0.98; women: OR 0.97, p < 0.05) and word list memory task scores (men: OR 0.84; women: OR 0.83, p < 0.05) in both sexes and SDST scores in women (OR 0.96, p = 0.04) were independent predictors of subsequent IADL limitation. Walking speed, memory, and processing speed may be independent predictors of IADL limitation in older adults.

Highlights

The loss of the ability to conduct daily activities leads to a rise in morbidity, caregiver burden, and mortality [1,2]
Women with instrumental activities of daily living (IADL) limitation were significantly older than men with IADL limitation; they exhibited significantly lower education levels, greater Geriatric Depressive Scale (GDS) scores, and slower walking speeds than those observed in the men (p < 0.01)
Limitation exhibited significantly higher scores on the Mini-Mental State Examination (MMSE) (p = 0.024) and Symbol Digit Substitution Test (SDST) (p < 0.01) than those observed in men with IADL limitation

Summary

Introduction

The loss of the ability to conduct daily activities leads to a rise in morbidity, caregiver burden, and mortality [1,2]. Everyday functioning ability in older adults consists of separate assessments of basic activities of daily living (BADLs) and instrumental activities of daily living (IADLs). BADLs are self-maintenance skills, such as bathing, dressing, and toileting, whereas IADLs are routine activities, but they are more goal oriented and related to more complex and higher functional abilities, such as preparing a meal, handling finances, shopping, and other activities [3,4]. Physical and cognitive status could be predictors for the onset of IADL limitation in older people [6,7]. Other studies have examined associations between baseline cognitive domains, including memory or executive function, and a decline in IADLs in older people [9,10]. Baseline cognitive functioning, executive function and memory, appear to be important predictors of the onset of IADL limitation

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