Multi-trajectories of intrinsic capacity and their effect on higher-level functional capacity, life satisfaction, and self-esteem in community-dwelling older adults: the NILS-LSA

Abstract

Objectives: Variability in intrinsic capacity (IC) changes among community-dwelling older adults and their effect on health outcomes remain understudied. We examined the variability in IC trajectories and their impact on higher-level functional capacity (HLFC), life satisfaction, and self-esteem. Design: Longitudinal study. Setting: Data from the second to seventh waves (2000–2012) of the National Institute for Longevity Sciences–Longitudinal Study of Aging project. Participants: 934 community dwellers (aged ≥60). Measurements: We used group-based multi-trajectory modeling to obtain IC trajectories across six domains: cognition, locomotion, vitality, vision, hearing, and psychological well-being. We employed multivariable regression to investigate the associations between IC trajectories and a decline in HLFC (assessed using the Tokyo Metropolitan Institute of Gerontology Index of Competence [TMIG-IC]; baseline TMIG-IC - follow-up TMIG-IC ≥ 2; logistic regression model), life satisfaction (assessed using the Life Satisfaction Index-K [LSI-K]; linear mixed model), and self-esteem (assessed using the Rosenberg Self-Esteem Scale [RSES]; linear mixed model). Results: We identified four IC trajectories: the “healthy aging group” (63.7%), the “hearing decline group” (15.1%), the “vision and cognitive decline group” (12.7%), and the “comprehensive deterioration group” (8.5%). Compared to the healthy aging group, the vision and cognitive decline group and the comprehensive deterioration group displayed a significantly greater risk of a decline in the TMIG-IC score (multivariable-adjusted odds ratio [aOR], 95% confidence interval [CI] = 2.05 [1.11, 3.79], 2.74 [1.41, 5.30], respectively), the LSI-K score (multivariable-adjusted β [standard error] = −0.46 [0.08], −0.52 [0.10], respectively), and the RSES score (multivariable-adjusted β [standard error] = −0.85 [0.16], −0.66 [0.20], respectively). The “hearing decline group” did not show a significantly increased risk for these outcomes. Conclusion: Older adults with different IC trajectories may differ in HLFC, life satisfaction, and self-esteem. Public health officials should be aware of this and provide targeted interventions.

Keywords

• Intrinsic capacity
• Trajectory
• Higher-level functional capacity
• Life satisfaction
• Self-esteem