Frailty Trajectories and Its Associated Factors in Japanese Older Adults.

Background: Associated factors for frailty development according to age group remain unclear.

Objectives: To identify frailty score trajectories among community-dwelling older Japanese individuals and examine their associated factors.

Design: 13-year longitudinal study.

Setting: Kusatsu Town in Gunma Prefecture, Japan.

Participants: 1706 older adults aged ≥ 65 years who completed an annual frailty assessment at least once between 2007 and 2019.

Measurements: Frailty status was determined using an index based on the Fried frailty phenotype criteria. Potential associated factors for frailty trajectory included physical, biological, lifestyle-related, and psychological factors, as well as comorbidities.

Results: We identified five trajectory patterns in the frailty score from age of 65 to 90 years -individuals who were robust (Group 1, 10.5%) as well as individuals with late-onset frailty (Group 2, 16.1%), middle-onset frailty (Group 3, 25.6% and Group 4, 35.2%), and early-onset frailty (Group 5, 12.7%). Compared with the other groups, the early-onset group showed a higher prevalence of cerebrovascular diseases, bone and joint diseases, poor nutrition, sarcopenia, hospitalization, low cognitive function, and smoking at the end of follow-up. Associated factors in the middle-onset group largely overlapped with those of the early-onset group. The late-onset frailty group tended to have a higher association with heart disease and bone and joint diseases compared with the robust group.

Conclusion: Our findings from a 13-year longitudinal study identified five frailty trajectory patterns and seven associated factors for frailty trajectory. Proposed effective population-based frailty prevention strategies in each age group may contribute to effective strategies to extend healthy life expectancy in aging, aged, and super-aged communities.