Exploring 2.5-Year Trajectories of Functional Decline in Older Adults by Applying a Growth Mixture Model and Frequency of Outings as a Predictor: A 2010-2013 JAGES Longitudinal Study.

Junko Saito,Yukako Tani,Katsunori Kondo,Masashige Saito,Daisuke Takagi,Takahiro Tabuchi,Naoki Kondo,Maho Haseda

doi:10.2188/jea.je20170230

Abstract

BackgroundWe explored the distinct trajectories of functional decline among older adults in Japan, and evaluated whether the frequency of outings, an important indicator of social activity, predicts the identified trajectories.MethodsWe analyzed data on 2,364 adults aged 65 years or older from the Japan Aichi Gerontological Evaluation Study. Participants were initially independent and later developed functional disability during a 31-month follow-up period. We used the level of long-term care needs certified in the public health insurance system as a proxy of functional ability and linked the fully tracked data of changes in the care levels to the baseline data. A low frequency of outings was defined as leaving one’s home less than once per week at baseline. We applied a growth mixture model to identify trajectories in functional decline by sex and then examined the association between the frequency of outings and the identified trajectories using multinomial logistic regression analysis.ResultsThree distinct trajectories were identified: “slowly declining” (64.3% of men and 79.7% of women), “persistently disabled” (4.5% and 3.7%, respectively), and “rapidly declining” (31.3% and 16.6%, respectively). Men with fewer outings had 2.14 times greater odds (95% confidence interval, 1.03–4.41) of being persistently disabled. The association between outing frequency and functional decline trajectory was less clear statistically among women.ConclusionsWhile the majority of older adults showed a slow functional decline, some showed persistent moderate disability. Providing more opportunities to go out or assistance in that regard may be important for preventing persistent disability, and such needs might be greater among men.

Highlights

Population aging has been observed and is accelerating worldwide
To improve our understanding of this association, we focused on the frequency of outings as a proxy indicator of the level of social activity and connectedness
We excluded those who had been certified for long-term care insurance (LTCI) or had died or moved before the survey date (n = 28), who moved out from their current residence during the followup period (n = 305), who lacked information on sex or age (n = 1,739), who required full assistance for activities of daily living (ADLs) (n = 165), or who died or were certified as needing long-term care within the first 3 months from baseline (n = 496). We excluded those who maintained their independence during the follow-up period (n = 36,999). This was because the proportion was too large (87.9% of those who had data matched with the LTCI database over 31 months) to ensure accurate classification of the trajectories of individuals requiring long-term care

Summary

Introduction

Population aging has been observed and is accelerating worldwide. The World Health Organization has proposed global strategies to maintain the functional ability and intrinsic capacity of older adults by removing barriers to participation and compensating for capacity losses.[1]. The Japanese government implemented a public long-term care insurance (LTCI) system in 2000 and has since faced the challenges of both sustaining the system financially and improving its performance in maintaining and improving the functional ability of those insured. To overcome these challenges, it is necessary to determine how older people’s functional ability changes and what environments are most conducive to declines. Han et al identified five distinct trajectories of functional ability among community-dwelling older adults: independent, consistently low or high disability, and a gradual change towards low or high disability.[3] In Japan, Liang et al classified three trajectories of functional impairment over 10 years: minimal function decrement, early onset and accelerated in the 80s, and late onset in the 70s–80s.4. We explored the distinct trajectories of functional decline among older adults in Japan, and evaluated whether the frequency of outings, an important indicator of social activity, predicts the identified trajectories

Methods

Results

Conclusion