The association between weight-adjusted-waist index and depression: Results from NHANES 2005–2018

The weight-adjusted-waist index (WWI) serves as an innovative obesity measure, seemingly surpassing body mass index (BMI) and waist circumference (WC) in evaluating lean and fat mass. This study aimed to explore the relationship between WWI and depression in United States (US) adults. This population-based study investigated adults with comprehensive WWI and PHQ-9 (9-item Patient Health Questionnaire) data from the National Health and Nutrition Examination Survey (NHANES) 2005–2018. WWI was computed by dividing WC by the square root of body weight. Weighted multivariate logistic regression and smoothed curve fitting were employed to examine linear and non-linear associations. Additionally, subgroup analyses and interaction tests were conducted. A total of 34,528 participants were enrolled with a prevalence of depression of 7.61 %. WWI was positively related to depression with the full adjustment [odds ratio (OR) = 1.21, 95 % confidence interval (95 % CI): 1.13–1.29]. After converting WWI to a categorical variable by quartiles (Q1–Q4), compared to Q1 the highest WWI quartile was linked to an obviously increased likelihood of depression (OR = 1.51, 95 % CI: 1.29–1.76). Subgroup analysis revealed the stability of the independent positive relationship between WWI and depression (all P for trend >0.05). WWI levels were positively related to an increased likelihood of depression in US adults. Our findings indicated that WWI may serve as a simple anthropometric index to predict depression.