Nonlinear Relationship of Weight‐Adjusted Waist Index With Self‐Reported Trouble Sleeping and the Mediating Role of Depression
Yuhan Song, Zhaoxiang Wang, Xuejing Shao, Shao ZhongPurpose
The weight‐adjusted waist index (WWI) is a novel measure for obesity that appears to outperform body mass index (BMI) and waist circumference (WC) in assessing lean and fat mass. Our aim was to explore the possible link between WWI and trouble sleeping.
Methods
This cross‐sectional study included 30,999 adults who participated in the National Health and Nutrition Examination Survey (NHANES) database. The WWI was calculated as WC (cm) divided by the square root of weight (kg). Trouble sleeping is based on a self‐reported medical history. The relationship between WWI and trouble sleeping was explored through logistic regression, smooth curve fitting, mediation analysis, and receiver operating characteristic (ROC) analysis.
Results
As WWI levels increase, self‐reported trouble sleeping becomes more prevalent (20.96% vs. 25.97% vs. 30.26% vs. 37.15%, p < 0.001). Multivariable logistic regression analysis showed that higher WWI was associated with a greater likelihood of self‐reported trouble sleeping (OR [95%CI]: 1.10 [1.03–1.18], p = 0.005). ROC analysis showed modest discrimination for WWI, with an area under the curve (AUC) of 0.6041. Smooth curve fitting uncovered a nonlinear relationship, with a breakpoint at 11.04. Additionally, depression partly mediated the WWI‐trouble sleeping connection.
Conclusions
Higher WWI was associated with a higher prevalence of self‐reported trouble sleeping. Although WWI may serve as a practical anthropometric indicator, its modest discriminatory ability and the cross‐sectional study design warrant cautious interpretation.