Successful ageing from old to very old: a longitudinal study of 12,432 women from Australia.

Objectives: We examined the development of disease and disability in a large cohort of older women, the extent to which these conditions exempt them from being classified as successful agers and different trajectories of disease, disability and longevity across women's later life.

Methods: We used survey data from 12,432 participants of the 1921-26 birth cohort of the Australian Longitudinal Study of Women's Health from 1996 (age 70-75) to 2016 (age 90-95). Repeated measures latent class analysis (RMLCA) identified trajectories of the development of disease with or without disability and according to longevity. Bivariate analyses and multivariable multinomial logistic regression models were used to examine the association between participants' baseline characteristics and membership of the latent classes.

Results: Over one-third of women could be considered to be successful agers when in their early 70s, few women could still be classified in this category throughout their later life or by the end of the study when they were in their 90s (~1%). RMLCA identified six trajectory groups including managed agers long survivors (9.0%) with disease but little disability, usual agers long survivors (14.9%) with disease and disability, usual agers (26.6%) and early mortality (25.7%). A small group of women having no major disease or disability well into their 80s were identified as successful agers (5.5%). A final group, missing surveys (18.3%), had a high rate of non-death attrition. Groups were differentiated by a number of social and health factors including marital status, education, smoking, body mass index, exercise and social support.

Conclusions: The study shows different trajectories of disease and disability in a cohort of ageing women, over time and through to very old ages. While some women continue into very old age with no disease or disability, many more women live long with disease but little disability, remaining independent beyond their capacity to be classified as successful agers.