Urban Accessibility or Social Inequality? A Multilevel Spatial Analysis of Built Environments and Type 2 Diabetes in Milan

Type 2 diabetes mellitus (T2DM) follows a social gradient; however, access to health-related services and amenities in urban areas may also impact its prevalence. This study investigates the association between characteristics of the built environment and T2DM prevalence in Milan, Italy. Utilising administrative health care data and open access territorial information, we examined the relationship between neighbourhood-level features and T2DM among the Milanese population in 2019. The analysis focused on six domains: food environment, physical activity infrastructure, cultural facilities, neighbourhood disorder, health care accessibility, and public transportation. We employed spatial analysis techniques based on road network buffers to evaluate potential access to health-related resources. Multilevel Poisson regression models, stratified by age group and sex, were applied to explore associations while adjusting for average neighbourhood educational attainment. Several built environment indicators demonstrated significant associations with T2DM; however, these associations lost statistical significance after controlling for area-level education. The influence of the built environment on health outcomes may differ in Milan's unique context compared to those settings where previous research has yielded consistent findings, particularly in the American context, which involves larger metropolises with greater urban heterogeneity and low- and middle-income countries characterised by notable urban/rural differences.