Functional Impairment and Decline in Middle Age: A Cohort Study.

ABSTRACT

BACKGROUND: Difficulties with daily functioning are common in middle-aged adults. However, little is known about the epidemiology or clinical course of these 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 to 56 years 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 for a maximum follow-up of 20 years, and impairment in instrumental ADLs (IADLs), defined similarly. Data were analyzed by using multistate models that estimate probabilities of different outcomes. RESULTS: Impairment in ADLs developed in 22% of participants aged 50 to 64 years, in whom further functional transitions were common. Two years after the initial impairment, 4% (95% CI, 3% to 5%) of participants had died, 9% (CI, 8% to 11%) had further ADL decline, 50% (CI, 48% to 52%) had persistent impairment, and 37% (CI, 35% to 39%) had recovered independence. In the 10 years after the initial impairment, 16% (CI, 14% to 18%) had 1 or more episodes of functional decline and 28% (CI, 26% to 30%) recovered from their initial impairment and remained independent throughout this period. The pattern of findings was similar for IADLs. LIMITATION: Functional status was self-reported. CONCLUSION: 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, current interventions used for prevention in older adults may hold promise for those in middle age. PRIMARY FUNDING SOURCE National Institute on Aging and National Center for Advancing Translational Sciences through the University of California, San Francisco, Clinical and Translational Sciences Institute.