Association between body roundness index and sleep disorder: the mediating role of depression

Several studies have indicated a potential association between obesity, depression, and sleep disorders. However, the role of depression in mediating the relationship between obesity and sleep disorders remains unclear. The Body Roundness Index (BRI), a more precise anthropometric measure of obesity than the traditional body mass index (BMI), is particularly effective in assessing body and visceral fat levels. This study examines the relationship between BRI and sleep disorders, with a focus on whether depression influences this association.

This study included data from 32,504 participants in the National Health and Nutrition Examination Survey (NHANES) 2005-2018 cycle. The association between BRI and sleep disorders was examined through subgroup analysis, restricted cubic spline (RCS) modeling, threshold effect analysis, and multivariable logistic regression. Furthermore, the predictive capabilities of various anthropometric indices-including BRI, weight-adjusted waist index (WWI), BMI, and weight-on sleep disorder incidence were assessed using Receiver Operating Characteristic (ROC) curve analysis. Finally, a Mediation analysis was also performed to explore the potential role of depression in this relationship.

This study included 32,504 participants, of whom 4,568 reported sleep disorders. After adjusting for all covariates using multivariable logistic regression, each one-unit increase in BRI was associated with a 13% higher prevalence of sleep disorders (OR = 1.13, 95% CI: 1.09, 1.16) and an 8% higher prevalence of depression (OR = 1.08, 95% CI: 1.05, 1.11). Similar results were obtained when BRI was divided into tertiles, with a significant trend (P for trend < 0.05). RCS and threshold effect analyses revealed a nonlinear relationship between BRI and sleep disorder prevalence, with a breakpoint of 3.508. The ROC curve analysis revealed that BRI had a superior predictive capability compared to traditional obesity indices, with an area under the curve (AUC) of 0.637 (95% CI, 0.628-0.645, all P < 0.001). Mediation analysis further indicated that 14% of the association between BRI and sleep disorders was mediated by depression (P < 0.001).

Elevated BRI levels were linked to a higher prevalence of sleep disorders, with depression acting as a partial mediator in this relationship. These findings emphasize the potential connection between obesity, depression, and sleep disorders, highlighting the importance of managing visceral fat to mitigate the risk of sleep disorders.

Not applicable.