Background/Purpose: Higher physical activity is linked to reduced fracture risk in older adults, especially for hip fractures. Emerging evidence demonstrates a potential role for the physical and built environment in promoting physical activity in community-dwelling, older adults. We aimed to evaluate whether neighborhood walkability and greenspace are associated with incident hip fracture in a large, community-dwelling, older adult population in the United States.

Methods: We conducted a retrospective analysis of 1992-2005 data from the prospective longitudinal Cardiovascular Health Study, a large cohort of community-dwelling adults aged ≥ 65 years from Winston-Salem, NC; Sacramento, CA; Hagerstown, MD; and Pittsburgh, PA. We included participants with a geocoded residential address at baseline (1992-1993 study visit) who were deceased as of July 2016 (to limit risks related to unintentional data disclosure). A participant’s neighborhood was defined as a 1-km Euclidean radial buffer surrounding their residential address at baseline. Neighborhood walkability was the sum of the standardized population density and density of walkable destinations for daily living, truncated at 5 due to a heavy upper tail. Neighborhood greenspace was the proportion of land uses classified as green or vegetated in the 1992 National Land Cover Dataset. Incident hip fractures were identified by participant report every six months from baseline, confirmed by hospital medical record review. Participants were followed for up to 12 years or until the occurrence of hip fracture, death, or loss to follow-up, whichever occurred first. Cox hazard models were used to evaluate associations of neighborhood walkability and greenspace with incident hip fracture in sex-stratified and combined analyses, adjusting for numerous fracture risk factors and socioeconomic metrics for the individual (marital status, education, annual household income) and neighborhood (median household income, median value of housing units, and proportion of persons in managerial or professional occupations), using study site as a random effect.

Results: Among 3,676 participants (mean age 75±5.5 years, 83% White/17% Black, 58% women) over a median 10 years of follow-up, we observed 506 hip fractures (365 in women, 141 in men). Greater neighborhood walkability was statistically significantly associated with lower incidence of hip fracture in women in fully adjusted models (hazard ratio: 0.84 per 1 unit higher neighborhood walkability, 95% confidence interval: 0.72-0.99) (Table 1). In contrast, neighborhood walkability was not statistically significantly associated with hip fracture in men (Table 1). There were no statistically significant associations between neighborhood greenspace and hip fracture (Table 1). Penalized spline plots revealed no significant non-linear relationships.

Conclusion: In this large, community-based cohort of older adults, greater neighborhood walkability was associated with lower hip fracture risk in women, highlighting a potential opportunity for urban planners to decrease fracture burden through walkable community design. No significant association was observed between neighborhood greenspace and hip fracture risk.

Table 1: Association of neighborhood walkability and greenspace with incident hip fracture: hazard ratios per 1 unit higher exposure in unadjusted, minimally adjusted, and fully adjusted Cox hazard models using study site as a random effect, overall and by sex

ACR Meeting Abstracts - https://acrabstracts.org/abstract/greater-neighborhood-walkability-is-associated-with-lower-incidence-of-hip-fracture-in-older-community-dwelling-women-in-the-united-states-the-cardiovascular-health-study/