Association between Weight-Adjusted Waist Index and Depression in NAFLD: the modulating roles of sex and BMI.

Background: The Weight-Adjusted Waist Index (WWI) is a novel indicator of obesity that accurately reflects body composition. However, the association between WWI and depression in patients with non-alcoholic fatty liver disease (NAFLD) remains unclear. This study aims to explore this relationship through a nationally representative cross-sectional analysis.

Methods: This study included adult participants diagnosed with NAFLD from NHANES 2017-2020. WWI was calculated as the waist circumference (cm) divided by the square root of body weight (kg). NAFLD diagnosis relied on vibration-controlled transient elastography (VCTE) with a controlled attenuation parameter (CAP) exceeding 248 dB/m to indicate hepatic steatosis. Depression was assessed using the Patient Health Questionnaire-9 (PHQ-9), with scores ≥ 10 indicating the presence of major depression.

Results: After adjusting for all covariates, a significant positive association was found between WWI and depression in NAFLD (OR = 1.725, 95% CI: 1.442-2.063, p < 0.00001), with a dose-response relationship indicated by restricted cubic spline analysis. The association was stronger in men and lean/normal weight NAFLD patients. Adjusting further for BMI did not alter these findings (OR = 1.643, 95% CI: 1.357-1.989, p < 0.00001). BMI's association with depression was negated after adjusting for WWI.

Conclusions: WWI had a positive association with depression in NAFLD, independent of BMI. This association was more pronounced in men and lean/normal weight NAFLD. These findings suggest that WWI may be a novel indicator of depression in NAFLD and potentially valuable in depression prevention.