Association between Body Roundness Index and diastolic function in middle-aged and older adults: a cross-sectional study

Background Diastolic dysfunction (DD) represents an early indicator of cardiac impairment and is strongly linked to adverse cardiovascular outcomes. While obesity-related indices have been associated with DD, the role of Body Roundness Index (BRI)-a novel adiposity measure reflecting body shape-remains unclear. This study aimed to evaluate the association between BRI and diastolic function in a community-based cohort. Methods This cross-sectional analysis included 1,466 participants from the Longitudinal Investigation of Osteoarthritis and Cardiovascular Health Status cohort. BRI was calculated using a validated formula, and DD was assessed via echocardiographic parameters. BRI's optimal cutoff was derived via 1000-iteration bootstrap ROC analysis. Multivariable regression models were used to evaluate associations, adjusting for age, sex, blood pressure, lipid profile, and cardiovascular comorbidities. Results Higher BRI was significantly associated with increased odds of DD. In fully adjusted logistic regression, each 1-unit increase in BRI was associated with 14.4% higher odds of DD (OR = 1.144, 95% CI: 1.046–1.251, P = 0.003). High BRI (≥4.2) was linked to 41.7% higher odds of DD (OR = 1.417, 95% CI: 1.114–1.804, P = 0.004). Robust regression confirmed BRI was inversely associated with septal e’ ( β = −0.164, P = 8.10 × 10 −4 ) and lateral e' velocities ( β =−0.167, P = 5.59 × 10 −3 ), and marginally positively associated with E/e' ratio ( β =0.121, P = 0.053). Restricted cubic spline models showed a nonlinear association between BRI and DD probability ( P < 0.001 for overall association, P = 0.006 for linearity). Interaction analyses indicated BRI's effect on DD was not modulated by blood pressure and lipid profiles. Subgroup analyses indicated a consistent trend of association between BRI and DD. Conclusions BRI is nonlinearly and independently associated with impaired diastolic function in middle-aged and older adults, with modest diagnostic performance. These findings provided evidence on the link between body shape metrics and DD.