Neighborhood walkability and physical activity among older women: Tests of mediation by environmental perceptions and moderation by depressive symptoms

Abstract

Features that enhance neighborhood walkability (higher population density, street connectivity and access to destinations) are associated with higher levels of physical activity among older adults. The perceived neighborhood environment appears to mediate associations between the objective built environment and physical activity. The role of depressed mood in these associations is poorly understood. We examined the degree to which depressive symptoms moderated indirect associations between the objective neighborhood environment and physical activity via the perceived neighborhood environment in older women. We analyzed data on 60,133 women (mean age = 73.1 ± 6.7 years) in the U.S. Nurses' Health Study cohort who completed the 2008 questionnaire. Self-reported measures included the Geriatric Depression Scale, perceived presence of recreational facilities, retail destinations, sidewalks, and crime, and participation in recreational physical activity and neighborhood walking. We created an objective walkability index by summing z-scores of intersection and facility counts within 1200-meter residential network buffers and census tract-level population density. We used multiple regression with bootstrap-generated 95% bias-corrected confidence intervals (BC CIs) to test for mediation and moderated mediation. Objective walkability was associated with 1.99 times greater odds of neighborhood walking (95% BC CI = 1.92, 2.06) and 1.38 times greater odds of meeting physical activity recommendations (95% BC CI = 1.34, 1.43) via the perceived neighborhood environment. These indirect associations were weaker among women with higher depressive symptom scores. Positive associations between objective neighborhood walkability and physical activities such as walking among older women may be strengthened with a reduction in their depressive symptoms.

Fig. 1.

Conceptual model of indirect and direct associations between objective neighborhood walkability and physical activity outcomes moderated by depressive symptoms among U.S. women nurses in 2008. Note: Model depicts perceived neighborhood environment as a potential mediator of the association between objective neighborhood walkability and physical activity.

Fig. 2.

Direct associations between objective neighborhood walkability, perceived neighborhood environment, and neighborhood walking among U.S. women nurses in 2008. Notes: Unstandardized regression weights (B) and the exponents of unstandardized logistic regression coefficients or odds ratios (OR) reported. Neighborhood walking defined as < 2 times or ≥2 times per week. Model adjusted for age, race, Hispanic ethnicity, nurse’s education, husband’s education, marital status, employment status, body mass index, previous chronic disease, and census tract-level household income. *Significant direct effect, tested using 95% confidence intervals (95% CIs) or significant indirect effect, tested using 95% bias-corrected confidence intervals (95% BC CIs).

Fig. 3.

Direct associations between objective neighborhood walkability, perceived neighborhood environment, and meeting physical activity recommendations among U.S. women nurses in 2008. Notes: Unstandardized regression weights (B) and the exponents of unstandardized logistic regression coefficients or odds ratios (OR) reported. Meeting physical activity recommendations defined as weekly average of < 500 or ≥500 MET minutes. Model adjusted for age, race, Hispanic ethnicity, nurse’s education, husband’s education, marital status, employment status, body mass index, previous chronic disease, and census tract-level household income. *Significant direct effect, tested using 95% confidence intervals (95% CIs) or significant indirect effect, tested using 95% bias-corrected confidence intervals (95% BC CIs).