Structural analysis of impact of physical, cognitive and social status on the incidence of disability in community-dwelling people aged ≥75 years.

Aim: The present study aimed to propose a structural model to explain the interaction of physical, cognitive and social domains of health status in the incidence of disability in community-dwelling people aged ≥75 years.

Methods: We analyzed 185 older adults (mean age 79.4 years, 58.4% female) who participated in a baseline assessment from 2012 to 2013. They were followed for incident certification of care needs in the national long-term care insurance certification system during the 2 years. Baseline assessments included several measurements related to the physical, cognitive and social domains of health status. We compared the model fit index between two hypothesis models - the parallel model and the hierarchical model - using structural equation modeling.

Results: During the follow-up period, 15 participants (8.1%) were newly certified as requiring personal support from the long-term care insurance system. The structural equation modeling showed that the hierarchical model, indicating that cognitive and social status were indirectly associated with disability through physical status, had a better fit with the data than the parallel model, indicating that physical, cognitive and social status each were directly associated with disability.

Conclusions: The present results suggest that cognitive and social status might indirectly affect disability incidence through physical aging. Further research is required to examine the temporal relationship between physical, cognitive and social change using data over several time-periods. Geriatr Gerontol Int 2018; 18: 1614-1619.