Neighborhood built environment and fracture risk among older adults: comparing high versus low clusters

Osteoporotic fracture is a leading cause of disability and a major contributor to medical care costs worldwide. Given that over half of fractures occur outdoors, understanding the relationship between the outdoor environment and fracture risk is essential. However, few studies have investigated the relationships between built environment and fractures. No study has explored how built environment attributes relate to fractures across different geographical areas. In this study, utilizing a five-year period of fracture data and fine-grained residential point data, we employed ordinal scan statistics to identify high and low fracture clusters among Japanese older adults. We then applied a zero-inflated ordered logit (ZIOL) model within each cluster to examine the associations between built environment attributes and fracture occurrence as well as fracture frequency. As a result, we identified one high and one low fracture clusters. In the low cluster areas, no significant associations were found between built environment attributes and fracture occurrence as well as fracture frequency. In contrast, in the high cluster areas, four individual built environment attributes-population density, intersection density, accessibility of bus services, and mix of function-showed statistically significant negative associations with fracture occurrence in their respective models. Notably, population density was particularly significant. This research provides valuable insights for developing preventions aimed at promoting active and independent aging by targeting specific neighborhood characteristics.