Abstract
IMPORTANCE: Emerging research suggests a complex interplay between physical health metrics and mental health outcomes, including suicidal ideation. The body roundness index (BRI), a novel measure of body size, may offer insights into this relationship. This study seeks to investigate the intricate connection between BRI and suicidal ideation in a sample that reflects the entire U.S. population-working to validate the potential of BRI as a predictor of suicidal ideation. METHODS: Data from the NHANES spanning 2013 to 2018 was used in this cross-sectional study to analyze a sample of 14,058 participants. BRI was calculated based on height and waist circumference measurements. Suicidal ideation was assessed using the Mental Health-Depression Screener Questionnaire ninth question. To investigate potential non-linear relationships between BRI and suicidal ideation, we employed generalized additive models and smooth curve fitting, and used ROC curves to compare the predictive ability of BMI and BRI for suicidal ideation. Subgroup analyses and interaction tests were utilized to study the moderating effects of categorical covariates. RESULTS: Multiple logistic regression analysis revealed a significant positive correlation between increased BRI and heightened suicidal ideation, with a nonlinear pattern persisting even after adjustment for covariates. This nonlinear relationship was reinforced by a sharp increase in the prevalence of suicidal ideation when the BRI exceeded 6.7. Based on ROC curve analysis, BRI demonstrates a slightly stronger predictive ability for suicide ideation compared to BMI. Subgroup analyses confirmed the relative robustness of this association across populations, including age, education and PRI, etc. However, the interaction between the two was influenced by gender, coronary artery disease and angina pectoris. CONCLUSION: In conclusion, our cross-sectional study reveals a significant positive correlation between increased BRI and heightened suicidal ideation, with a sharp increase in prevalence when BRI exceeds 6.7. It is recommended that appropriate BRI be maintained to minimize suicidal ideation.