Are self-reported neighbourhood characteristics associated with onset of functional limitations in older adults with or without memory impairment?

Background Neighbourhood resources may preserve functional independence in older adults, but little is known about whether benefits differ for individuals with normal and impaired memory. We evaluated the extent to which neighbourhood context was related to onset of instrumental and basic activities of daily living (I/ADL) limitations and whether relationships were modified by memory impairment. Methods Health and Retirement Study participants 50+ years of age without baseline I/ADL limitations (n=8726 for IADL and n=8345 for ADL models) were interviewed biennially for up to 8years. Self-reported neighbourhood characteristics were scaled from 0 (worst) to 1 (best). Memory, assessed by direct and proxy cognitive assessments, was dichotomised at the 20th centile. We used pooled logistic regression models, adjusted for demographics and individual characteristics. Results Low neighbourhood physical disorder (OR=0.51 (95% CI: 0.37 to 0.69)), high social cohesion (OR=0.46 (0.34 to 0.62)), and high safety (OR=0.59 (0.46 to 0.76)) were associated with reduced incidence of IADL limitations. These neighbourhood characteristics were also associated with lower incidence of ADL limitations (disorder OR=0.59 (0.43 to 0.81)); social cohesion OR=0.60 (0.45 to 0.81)); safety OR=0.74 (0.58 to 0.93)). High social ties were not related to ADLs (OR=1.01(0.80 to 1.28)) or IADLs (OR=0.93(0.74 to 1.17)). The benefits of these neighbourhood characteristics for ADLs were similar among those with and without memory impairment but primarily observed among those without memory impairment for IADLs. Conclusions Older adults living in neighbourhoods with low physical disorder, high social cohesion and high safety experience lower incidence of IADL and ADL limitations. Memory status modified the estimated effects of neighbourhood characteristics on IADL but not ADL limitations.