Elevated body roundness index and epilepsy prevalence: a cross-sectional study

Obesity and epilepsy have a complex bidirectional relationship. Body mass index is commonly used to study this association but does not capture fat distribution. The Body Roundness Index (BRI) reflects abdominal adiposity. To our knowledge, the association between BRI and epilepsy prevalence has not been reported. We analyzed 17,914 adults from NHANES 2013-March 2020. BRI was modeled continuously and by tertiles. We used logistic regression to estimate odds ratios (ORs) and 95% CIs for prevalent epilepsy. Restricted cubic spline analyses evaluated nonlinearity. Prespecified sensitivity analyses excluded participants taking valproate (n = 6) or carbamazepine (n = 23). Variance inflation factors assessed multicollinearity. No nonlinear relationship between BRI and epilepsy (P = 0.609). Higher BRI was associated with greater odds of prevalent epilepsy in fully adjusted models (per-unit OR, 1.08; 95% CI 1.01-1.15; P = 0.03). Compared with Q1, Q3 showed higher odds (OR, 1.73; 95% CI 1.06-2.89; P = 0.03), whereas Q2 did not reach significance (OR, 1.58; 95% CI 0.97-2.63; P = 0.07). Findings were materially unchanged after excluding valproate or carbamazepine users. Subgroup point estimates exceeded 1 across strata; tests for interaction were not significant. Higher BRI is associated with higher prevalence of epilepsy. These results underscore the potential importance of abdominal fat distribution in epilepsy and warrant confirmation in larger prospective studies.