Neighborhood Walkability, Green Space, and Incident Hip Fracture among Older U.S. Adults: The Cardiovascular Health Study.

PURPOSE: Neighborhood walkability and green space are associated with walking behavior and physical activity, but evidence linking them to fracture is limited and inconsistent, and potential sex differences remain understudied. We evaluated associations of neighborhood walkability and green space with incident hip fracture in older, community-dwelling U.S. adults.

METHODS

We conducted a prospective cohort study of adults aged ≥65 years from the Cardiovascular Health Study (CHS). Neighborhood exposures were defined using 1-km radial buffers around geocoded residential addresses from 1992-1993 (baseline). Walkability was the sum of standardized population and walkable destination densities. Green space was the proportion of satellite-derived green land cover. Hip fractures were prospectively ascertained over 12 years using International Classification of Diseases, Ninth Revision (ICD-9) codes from hospital discharge abstracts. Cox hazard models adjusted for individual-level (age, sex, race, weight, height, smoking status, current heavy alcohol use, medication use, diabetes, renal function, marital status, education level, annual household income) and neighborhood-level (median household income, median value of owner-occupied housing, proportion of persons in managerial/professional occupations) covariates evaluated associations, overall and by sex.

RESULTS

Among 3,676 participants (58% women), 359 experienced hip fracture over a median 10-years observation. Greater neighborhood walkability was significantly associated with lower hip fracture incidence among women (hazard ratio per 1 standard deviation increase of 0.72 [95% confidence interval, 0.53-0.98]), but not overall or among men. Neighborhood green space was not significantly associated with hip fracture.

CONCLUSION

Greater neighborhood walkability, but not green space, was associated with lower hip fracture risk among older women.