Determinants of rate of change in functional disability: An application of latent growth curve modeling

Our aim was to identify disablement factors, including predisposing, intra-individual, and extra-individual factors, which predict the rate of change in general functional disability (GFD) in older adults. This study utilized the Taiwan Longitudinal Study on Aging Survey in 1996-2007 (N=3,186). Multiple-indicator latent growth curve modeling was used to examine how 12 disablement factors predicted the rate of change in GFD. GFD trajectories were modeled using Nagi's functional limitations, activities of daily living, and instrumental activities of daily living. Greater age (B=.025), female gender (B=.114), and greater numbers of comorbidities (B=.038) were associated with faster increase in GFD. Education (B=-.005) and participation in physically active leisure time activities (B=-.031) were associated with slower increase in GFD. Our findings add to the understanding of how disablement factors contribute to the rate of change in GFD. Predisposing factors played the main role. However, the factors we found to be associated with the rate of change in GFD in older adults were slightly different from the factors reported in the literature. Decreasing the number of comorbidities and increasing the level of physically active leisure time activity should be considered priorities for preventing disability as people age.