Association between Weight-Adjusted Waist Index and depressive symptoms: A nationally representative cross-sectional study from NHANES 2005 to 2018

Depressive symptoms are strongly associated with the development of various diseases and are one of the leading causes of disability in the world. However, the relationship between weight-adjusted waist index (WWI) and depressive symptoms has not been studied. This study aimed to assess the relationship between depressive symptoms and WWI. This study took NHANES data from 2005 to 2018 with 32,374 participants. Depressive symptoms were measured by a questionnaire (PHQ-9).WWI was determined by dividing the square root of waist circumference (cm) by weight (kg). Multivariate logistic regression models, smoothed curve fitting, and weighted generalized additive model (GAM) regression were used to examine the relationship between depressive symptoms and WWI, BMI, and waist circumference. Subgroup analyses and interaction tests were also performed. In fully adjusted models, the OR (95 % CI) for WWI and depressive symptoms with WWI, BMI, and waist circumference were 1.18 (1.05, 1.34), BMI 1.01 (1.00, 1.02, 1.01 (1.00, 1.01), respectively. Participants in the highest quartile (Q4) had a 49 % higher depressive symptoms compared to those in the lowest quartile (Q1) (OR = 1.49, 95 % CI:1.14–1.96). Subgroup analyses and interaction tests showed a stable relationship between depressive symptoms and WWI. It is difficult to determine a causal relationship between the two; questionnaire collection may be somewhat biased; WWI was positively associated with depressive symptoms. This association was stronger than BMI and waist circumference. However, this relationship was stable. This study emphasizes the potential utility of WWI in preventing depressive symptoms and improving prognosis in the population.