Predictors for the onset of functional decline among initially non‐disabled older people living in a community during a 6‐year follow‐up

Abstract

Background: Predictors for functional decline in basic activities of daily living (BADL) among older people have been extensively studied. However, relatively little is known about predictors for decline in instrumental activities of daily living (IADL).Objectives: To identify predictors for functional decline in IADL as well as predictors for decline in BADL among initially non‐disabled older people living in a community by a longitudinal epidemiological study.Methods: Out of 748 older persons aged 65 years and over who participated in the interview survey and medical examination at baseline in 1992, 601 persons were identified as being independent in both BADL and IADL, and were followed‐up yearly for 6 years until 1998. Outcome events were the onset of IADL disability prior to the onset of BADL disability as well as the onset of BADL disability. A wide range of variables obtained in the baseline survey was entered into the model predicting functional decline in BADL and IADL during the follow‐up period.Results: Common predictors for BADL and IADL disability included: (1) advanced age; (2) lower levels in performance‐based measures; (3) a history of hospitalization in the past year; and (4) poor chewing ability. Longer sleep‐hours, poor intellectual activities, and poor self‐rated health were identified as significant predictors for only IADL disability. Not having an occupation, a history of heart disease, and higher blood β2‐microglobulin level were identified as a significant predictors of BADL disability.Conclusions: Good intellectual activities, good self‐rated health, good chewing ability, and good physical performance are closely associated with remaining independent in IADL for non‐disabled older people. Significance of blood β2‐microglobulin in predicting the onset of functional decline merits further study.