Nonlinear association between body roundness index and metabolic dysfunction associated steatotic liver disease in nondiabetic Japanese adults

Abstract

Abstract The global rise in obesity and diabetes has been paralleled by a rising incidence of metabolic dysfunction-associated steatotic liver disease (MASLD). Although previous studies have explored the association between body roundness index (BRI) and MASLD, the specific relationship in non-diabetic Japanese adults requires further investigation. This study analyzed data from 15,299 participants enrolled in the NAGALA cohort (2004–2015) to explore the association between BRI and MASLD through multivariable logistic regression, stratified analysis, and restricted cubic spline modeling. The prevalence of MASLD was 14.46%, with 13.73% occurring in non-obese individuals (BMI < 30). After adjusting for all confounding factors, BRI demonstrated a significant association with MASLD, yielding an adjusted odds ratio of 1.72 (95% CI 1.48–1.99). The restricted cubic spline model revealed a nonlinear relationship, with an inflection point at 3.06. Stratified analyses revealed stronger associations in individuals with lower BMI (≤ 24 kg/m2).