Predictors of mobility decline: the Hong Kong old-old study.

Abstract

Old age is often accompanied by functional decline and loss of autonomy. This longitudinal study examines the factors associated with mobility decline among a Chinese elderly cohort aged 70 years and above. Analyses were carried out on data collected from 1,483 elderly subjects who were functionally mobile at baseline and survived the 18-month follow-up period. The outcome variable "mobility decline" was measured using the Barthel Activities of Daily Living Scale, which accesses subjects' ability to be independent in walking a distance of 50 meters and/or moving up and downstairs during the 18-month follow-up interview. Multivariate backward stepwise logistic regression analysis revealed that the following baseline characteristics were independently associated with mobility decline during the follow-up period: increasing age (OR 1.4, 95% CI 1.2-1.6 for every 5-year increase in age), no formal level of education (OR 1.9, 95% CI 1.0-3.9), no current practice of exercise (OR 2.1, 95% CI 1.4-3.1), symptoms of palpitation (OR 1.7, 95% CI 1.1-2.8), body mass index [weight (kg)/height (m)2] below 20 (OR 1.7, 95% CI 1.1-2.6), and slow gait velocity (OR 1.12, 95% CI 1.09-1.16 per second increase in gait time). There was also significant association between the experience of falls during follow-up and mobility decline (OR = 2.9, 95% CI = 1.9-4.5). Low body weight, lack of exercise, and falls during the follow-up period might serve as markers as to which subjects are at risk for mobility decline.