Associations Between Active Mobility Index and Disability.

Abstract

To develop a questionnaire-based Active Mobility Index (AMI) to assess going-out behavior with physical and social activity among older adults, and to assess the criterion-related and predictive validity of the AMI. Prospective cohort study. General community setting. Participants comprised 4432 older adults [mean age: 75.9 ± 4.3 (70-96) years; 2100 men (47.4%)]. AMI assessed life-space and activities in each life-space (distance from the respondent's home: <1km, 1-10km, or >10km) according to physical or social activity during the past 1month by noting frequency, purpose, type of transportation, interaction with others, and physical activity. Baseline characteristics and outcomes were compared by AMI score quartiles (highest: Q4). To examine the criterion-related validity of AMI, depressive symptoms, frailty, and cognitive function were assessed. During follow-up, incident disability was monitored by Long Term Care Insurance certification. Lower scores (Q1-Q3 groups) were associated with more depressive symptoms, frailty, and cognitive impairment compared with the Q4 group (all P < .001). Multiple logistic regression analyses revealed significantly higher odds ratios in the Q1 group in all health adverse outcomes compared with the Q4 group [depressive symptoms, odds ratio (OR) 3.94, 95% confidence interval (CI) 2.95-5.28; frailty, OR 3.20, 95% CI 2.31-4.44; cognitive impairment, OR 1.28, 95% CI 1.04-1.57]. Cox proportional hazards modeling indicated that the Q1 group had a higher risk of incident disability compared with the group (hazard ratio 1.53, 95% CI 1.24-1.88). AMI to assess life-space with physical and social activity among older people was associated with depressive symptoms, frailty, and cognitive impairment. Lower AMI scores were associated with higher incident disability risk. Further studies are needed to elucidate whether AMI is causally associated with incident adverse health outcomes.