To investigate the interaction between subjective aging and higher-level life functions (i.e., life functions beyond instrumental ADL) among community-dwelling older adults.
A mail survey using a questionnaire originally developed for this study was conducted among older adults aged ≥65 years (N=8,004) living in Koryo Town, Nara Prefecture, Japan. The baseline survey (Time 1: T1) was conducted in 2016, with 3,871 respondents (response rate: 48.3%). A follow-up survey (Time 2: T2) was conducted with 3,121 individuals, excluding those certified as requiring support or care. From the data of 2,646 individuals available for the three-year follow-up from baseline, 2,413 individuals were included in the analysis. According to a previous study (Stephan et al., 2013), subjective age can be assessed by asking participants to specify how old they feel. To standardize the gap between subjective and chronological ages, the subjective age discrepancy (SAD) was calculated as the difference between chronological and subjective ages, divided by the chronological age. A higher discrepancy score indicates a younger subjective age. A construct variable for “youthful mind” was constituted by SAD and the total score of the General Self-Efficacy Scale, and “higher-level life function” was defined from scores on the Tokyo Metropolitan Institute of Gerontology Index of Competence and the Japan Science and Technology Agency Index of Competence, the degree of trust in neighbors, and practice norms of reciprocity. A cross-lagged and synchronous effects model was performed to examine the interaction between “youthful mind” and “higher-level life function.”
In a cross-lagged effect model, the path from “higher-level life function” (T1) to “youthful mind” (T2) was significant (β=.20, p.05; large effect), indicating that “higher-level life function” influenced the “youthful mind” three years later. However, the opposite relationship was not significant. The model fit the data reasonably well (goodness of fit index [GFI]=0.95, adjusted goodness of fit index [AGFI]=0.92, comparative fit index [CFI]=0.92, and root mean square error of approximation [RMSEA]=0.07). A synchronous effects model only showed a significant pathway from “Higher-level life function” at T2 to “Subjective youth” at T2, and the opposite direction was not significant. The model fit the data reasonably well (GFI=0.95, AGFI=0.92, CFI=0.92, RMSE=0.07).
Among community-dwelling older adults, expanding higher-level life functions beyond instrumental ADL may suppress subjective aging after three years, but the opposite relationship may not be established.
Building social networks and mutually supportive relationships with neighbors in a community can prevent social frailty and excessive psychological ageing.
life functions
subjective age
