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

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

13-year longitudinal study.

Kusatsu Town in Gunma Prefecture, Japan.

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

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.

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.

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.