Onset and progression of chronic disease and disability in a large cohort of older Australian women

Abstract

Objective: To estimate the probability of onset and progression of disease and disability, length of life with or without disease and/or disability, and incidence of mortality, and to identify factors associated with transitioning to disease and/or disability over time. Study design: A prospective cohort study. Data were provided by 12,432 participants (born 1921–26) of the Australian Longitudinal Study of Women’s Health linked with National Death Index data from 1996 (age: 70–75) to 2016 (age: 90–95). Main outcome measures: A five-state Markov model was fitted to estimate the transition probability, length of life with or without disease and/or disability, and the association between baseline characteristics and disease/ disability/mortality risk. Results: Over two-thirds of women had died by age 90–95, and only 3.8% of these had died with no chronic disease and disability. Those reporting chronic disease were more likely to have experienced disability (Tran- sition Rate Ratio: 2•72, 95%CI= 2•52–2•93) than those who died without disability. At age 70–75, the expected life without chronic disease and disability was 7•68 (95%CI: 7•52–7•80) years, life with chronic disease but no disability was 4•39 (95%CI=4•23–4•49) years, and life with disability was 3.76 (95%CI=3•66–3•92) years. The factors difficulties managing on available income (HR=1•18, 95%CI=1•02–1•38), did not complete secondary school (HR=1•19, 95%CI=1•03–1•37), and overweight/obese (HR=1•36, 95%CI=1•20–1•55) were associated with an increased risk of disability. Conclusions: Our findings provide important insights on the onset and progression of disease and disability in older women, underscoring the importance of addressing mid-/early old-life risk factors, managing chronic conditions, and delaying disability onset and progression through targeted intervention programs.