Geospatial predictors of vitamin D deficiency across London involve complex interactions between the social and built environment

Vitamin D deficiency is a global public health concern, causing musculoskeletal complications and linked with COVID-19, cancer and other morbidities. Global prevalence is high, even in countries with abundant sunshine, suggesting a complex aetiology. Vitamin D deficiency disproportionately impacts people with higher skin melanin content, thus potentially exacerbating health inequalities amongst ethnically minoritised communities. Whilst vitamin D is acquired most efficiently through sunlight, this can be restricted in urban areas with high population and building density. Furthermore, air pollution may interfere with vitamin D synthesis by blocking UVB photons. Given that over 68% of the global population are expected to live in cities by 2050, it is essential to explore environmental barriers and opportunities to prevent vitamin D deficiency.Drawing upon data from the UK Biobank and UK Data Service, we conducted a geographically weighted regression (GWR) analysis to predict features of the built environment that may contribute to vitamin D deficiency across London. Our GWR model is the first to identify heterogeneity in the relationship between air pollution and vitamin D across London and suggests this can be explained by the hyperlocal social and built environment. Our results describe several significant modifiable predictors of vitamin D at the Middle Layer Super Output Area (MSOA), including greenspace, air pollution and road network variables (p