Fig. 1

Study workflow. This study analyzed data from 321,596 UK Biobank participants, tracking outcomes for mental disorders, including depressive disorder, substance use disorder, and anxiety disorder, with psychiatric symptoms and alterations in brain white matter as secondary outcomes. (A) The study cohort, including population flowchart and baseline characteristics. (B) Body roundness index. (C) Cox proportional hazards regression models were applied to examine associations between BRI levels and mental disorders risk. Hazard ratios (HRs) and the corresponding 95% confidence intervals (CIs) were calculated in our analyses. Subgroup analyses were conducted stratified by age (< 60/≥60), sex (male/female), region (urban/other), and prevalent diseases (yes/no). Further analyses were also utilized to estimate the relationships of BRI levels with psychiatric symptoms and impairments of brain white matter by logistic regression models and multiple linear regression models, respectively.