How neighborhood socioeconomic status, green space, and walkability are associated with risk for fracture among postmenopausal women

Although most fractures, and about half of hip fractures, occur outdoors among older women, limited research has uncovered neighborhood predictors for fractures among older women. This study assessed the independent associations of neighborhood socioeconomic status (SES), walkability, and green space with incident any and hip fracture among postmenopausal women. The Women's Health Initiative recruited a national sample of postmenopausal women (50-79 yr) across 40 U.S. clinical centers and conducted yearly assessments from 1993 to 2012 (<i>n</i> = 161 808). Women reporting a history of hip fracture or walking limitations were excluded from the analytic sample, yielding a final sample of 157 583 participants. Fracture events were self-reported and adjudicated annually. Walkability was calculated annually using measures of population density, land use mix, and presence/quantity of nearby high-traffic roadways. Neighborhood green space was calculated annually using measures of exposure to trees/vegetation. Neighborhood SES, walkability, and green space were categorized into tertiles: high, intermediate, and low. The time-varying relationship between neighborhood environmental factors and age at first fracture (any; hip) was examined using extended Cox proportional hazards modeling with adjustment. Neighborhood SES (intermediate vs low: hazard ratio = 1.03, 95% CI, 1.01-1.05; high vs low, hazard ratio = 1.01, 95% CI, 0.99-1.03) and green space (intermediate vs low, hazard ratio = 1.15, 95% CI, 1.12-1.18; high vs low hazard ratio = 1.18, 95% CI, 1.15-1.21) were associated with increased any incident fractures, while walkability had a mixed association (intermediate vs low hazard ratio = 1.06, 95% CI, 1.04-1.07; high vs low, hazard ratio = 0.97, 95% CI, 0.95-0.98). Neighborhood SES, walkability, and green space did not have a relationship with hip fracture after adjustment for important covariates. Results indicate that macroscale neighborhood features did not protect against fractures. Additional research is needed to investigate more granual neighborhood features that might influence injury risk and support physical activity among postmenopausal women.