Longitudinal relationship between weight-adjusted waist index and depressive symptoms in middle-aged and older Chinese adults: A prospective cohort study.

The association between obesity and depressive symptoms remains controversial. The Weight-adjusted waist index (WWI) shows advantages in assessing central obesity. This study aimed to investigate the longitudinal relationship between WWI and depressive symptoms. This prospective cohort study utilized data from the China Health and Retirement Longitudinal Study (CHARLS) spanning 2011–2020. Depressive symptoms were assessed using the 10-item Center for Epidemiological Studies Depressive Symptoms Scale (CESD-10) scores. Linear mixed models were used to examine longitudinal associations. A total of 6835 participants over the age of 45 were included. WWI was positively associated with CESD-10 scores (β per 1 SD increase = 0.052SD; 95%CI: 0.021 to 0.083SD) and was linked to a faster increase in CESD-10 scores over time (β = 0.095SD/year; 95%CI: 0.090 to 0.100 SD/year). Conversely, BMI was negatively associated with CESD-10 scores (β per 1 SD increase = −0.067SD; 95%CI: −0.097 to −0.038SD). However, the negative association between BMI and CESD-10 scores weakened over time (β per 1 SD increase = 0.008SD/y; 95%CI: 0.003 to 0.013 SD/y). Nonlinear associations were detected between both WWI and BMI with CESD-10 scores. Self-reported depressive symptoms assessments may have introduced information bias. The observational design limits ruling out unobserved confounding factors. Our findings highlight the association between WWI and the long-term progression of depressive symptoms in middle-aged and older adults. WWI may enhance our understanding of the link between obesity and depressive symptoms and could be superior to BMI in predicting depressive symptom progression. • The association between obesity and depression remains controversial. • Weight-adjusted Waist Index has advantages in reflecting abnormal body composition. • Heterogeneity in depression trajectories was detected among older adults. • Weight-adjusted Waist Index may accelerate the progression of depression. [ABSTRACT FROM AUTHOR]