Life-Space Mobility and Frailty in Older Japanese Adults: A Cross-Sectional Study

Objectives: Some studies reported a relationship between life-space mobility (LSM) and frailty assessed by physical aspects; however, a more comprehensive discussion of frailty is underdeveloped. In addition, previous studies have focused only on older Euro-American people. Therefore, we aimed to examine LSM-frailty relationships in community-dwelling older Japanese persons using physical and comprehensive frailty indices. Design: A cross-sectional study. Setting and Participants: We used the data of 8898 older adults from a baseline survey of the Kyoto-Kameoka Study in Japan. Methods: The validated life-space assessment (LSA) was used to evaluate LSM and categorized it into quartiles. Two validated indices were used to evaluate frailty: the Kihon Checklist (KCL) and the simple Frailty Screening Index (FSI). Multivariable logistic regression was used to determine the relationships between LSM scores and frailty. Results: The mean age (SD) of the participants was 73.4 (6.3) years, and 53.3% were women. The mean LSM score of the study participants was 53.0. The prevalence of frailty by KCL and FSI was 40.7% and 16.8%, respectively. Significant differences between LSM score and frailty prevalence were observed [KCL: Q1, reference; Q2, odds ratio (OR) 0.53, 95% CI 0.45-0.62; Q3, OR 0.30, 95% CI 0.25-0.35; Q4: OR 0.22, 95% CI 0.18-0.26, P for trend <.001; FSI: Q1, reference; Q2, OR 0.57, 95% CI 0.48-0.68; Q3: OR 0.38, 95% CI 0.31-0.46; Q4: OR 0.35, 95% CI 0.28-0.42, P for trend <.001]. Similar results were observed when LSM scores were examined at 10-point intervals, with LSM and frailty exhibiting an L-shaped relationship. The LSM score dose-response curve at which the OR for frailty plateaued among older individuals was approximately 81-90 score. Conclusions and Implications: LSM score and frailty prevalence exhibited L-shaped relationships in community-dwelling older persons. This study's findings provide useful data for setting LSM targets for preventing frailty in community-dwelling older persons.