Disentangling residential self-selection from the influence of built environment characteristics on adiposity outcomes among undergraduate students in China

Although many studies have confirmed the effects of the built environment on adiposity outcomes in the general population, evidence for young adults is scarce. Furthermore, most prior studies are prone to residential self-selection bias due to the nature of cross-sectional research design, which makes the built environment–adiposity relationship spurious. In this study, we explored the associations between the built environment and three objectively measured adiposity outcomes for a large representative sample of 20,227 undergraduate students from 89 university campuses in China. The adiposity outcomes were measured by body mass index (BMI), waist circumstance (WC), and waist-to-height ratio (WHtR). The residential self-selection bias was largely mitigated because these students are required to live in campus dormitories. As shown by multilevel models, street connectivity, population density, and Normalized Difference Vegetation Index (NDVI) within and around the campus environment were negatively associated with the odds of adiposity to different extents. Furthermore, the adiposity outcomes of male and low cost-of-living undergraduates were more likely to be affected by built environment characteristics compared to female and high cost-of-living undergraduates. Hence, to deliver effective environment interventions to curb the prevalence of adiposity among undergraduate students, policymakers and university managers are advised to create a more carefully conceived campus environment.