Socioeconomic and Lifestyle Factors Related to Instrumental Activity of Daily Living Dynamics: Results from the English Longitudinal Study of Ageing

OBJECTIVES: To investigate socioeconomic, demographic, and lifestyle factors that predict incident instrumental activity of daily living (IADL) impairment and recovery. DESIGN: Data from English Longitudinal Study of Ageing (ELSA), a biennial prospective observational study. SETTING: Individuals aged 50 and older living in England. PARTICIPANTS: A sample of 8,154 individuals without any difficulty in activities of daily living (ADLs) or IADLs was selected from the initial 11,391 participants. MEASUREMENTS: The first outcome was impairment in at least one IADL, and the second was IADL recovery. Main predictor: baseline socioeconomic position measured according to wealth. Outcomes and predictors were measured at each of the five follow-up interviews. Unadjusted and adjusted incidence rate ratios (IRR) and 95% confidence intervals were calculated through 2-year lagged Poisson regression in generalized estimating equation models, adjusted for sociodemographic, lifestyle, quality-of-life, and health variables. RESULTS: Between any two consecutive waves, 1,656 (20.3%) participants developed some IADL impairment. Those with higher socioeconomic position, better quality of life, vigorous physical activity, paid work, digital literacy (use of Internet or e-mail), and cultural leisure activities had significantly lower risk of IADL impairment. There was a significant association between smoking, cardiovascular disease, arthritis, poor memory, diabetes mellitus, and depressive symptoms and IADL impairment. Better quality of life, good self-rated memory and vigorous physical activity were independent predictors of IADL recovery. CONCLUSION: Better quality of life, vigorous physical activity, not smoking, paid work, cultural leisure activities, and digital literacy are modifiable factors that can decrease the incidence of IADL impairment. Good quality of life and vigorous physical activity have a significant role in recovery. Low socioeconomic position was a predictor of incident impairment of IADLs but not recovery.