Background
Difficulties with daily functioning are common in middle-aged adults. However, little is known about the epidemiology or clinical course of these functional problems, including the extent to which they share common features with functional impairment in older adults.
Objective
To determine the epidemiology and clinical course of functional impairment and decline in middle age.
Design
Cohort study.
Setting
The Health and Retirement Study.
Participants
6874 community-dwelling adults aged 50–56 who did not have functional impairment at enrollment.
Measurements
Impairment in activities of daily living (ADLs), defined as self-reported difficulty performing 1 or more ADLs, assessed every 2 years over a maximum follow-up period of 20 years, and impairment in instrumental ADLs (IADLs), defined similarly. Data were analyzed using multi-state models which estimate probabilities of different outcomes.
Results
Twenty-two percent of participants developed ADL impairment between ages 50 and 64. Among these individuals, further functional transitions were common. Two years after the initial impairment, 4% (95% CI, 3%–5%) of participants had died, 9% (CI, 8%–11%) had experienced further ADL decline, 50% (CI, 48%–52%) had persistent impairment, and 37% (CI, 35%–39%) had recovered independence. In the 10 years following the initial impairment, 16% (CI, 14%–18%) had one or more episodes of functional decline, and 28% (CI, 26%–30%) recovered from their initial impairment and remained independent throughout. The pattern of findings was similar for IADLs.
Limitations
Functional status was self-reported.
Conclusions
Functional impairment and decline are common in middle age, as are transitions from impairment to independence and back again. Because functional decline in older adults has similar features, interventions currently used to prevent functional decline among older adults may hold promise for adults in middle age.
Primary Funding Source
National Institute on Aging and the National Center for Advancing Translational Sciences through the UCSF-Clinical and Translational Sciences Institute