Associations of a Body Shape Index and Conicity Index With Self-Reported Suicidal Ideation: NHANES 2005–2018

Objective Suicidal ideation (SI) is an important public health concern. Increasing evidence suggests that central obesity may be associated with adverse mental health outcomes; however, the relationships of a body shape index (ABSI) and conicity index (CI) with self-reported SI remain unclear. This study aimed to investigate the associations of ABSI and CI with SI among U.S. adults. Methods This cross-sectional study was based on data from the National Health and Nutrition Examination Survey (NHANES) 2005-2018. Weighted multivariable logistic regression was used to evaluate the associations of ABSI and CI with self-reported SI. Quartile-based analyses, restricted cubic spline (RCS) analyses, subgroup analyses, receiver operating characteristic (ROC) analyses, and sensitivity analyses were also performed. Results The survey-weighted prevalence of self-reported SI was 3.19% (95% CI, 2.90%–3.51%). In the fully adjusted model, ABSI (odds ratio (OR): 1.140; 95% CI: 1.023, 1.270; P = 0.018) and CI (OR: 1.151; 95% CI: 1.043, 1.269; P = 0.006) were associated with the self-reported SI. RCS analyses suggested approximately linear associations. An interaction was observed between CI and diabetes status (P for interaction = 0.020), although this finding was exploratory. The results remained generally consistent after additional adjustment for antidepressant use and multiple imputation. Conclusion Higher ABSI and CI were modestly associated with greater odds of self-reported SI, with approximately linear dose-response relationships. Prospective studies are needed to confirm the temporal and causal nature of these associations.