Associations between serum uric acid and risk of depressive symptoms in East Asian populations

Despite the fact that observational studies have reported associations between serum uric acid (SUA) and depressive symptoms risk in East Asian populations, there is a lack of evidence demonstrating a causal relationship between them. This study aimed to perform a comprehensive assessment of the relationship between SUA and depressive symptoms.

This study included two cohort studies and a two-sample Mendelian randomization study. The cross-sectional cohort was derived from the China Health and Retirement Longitudinal Study (CHARLS) wave 3 (in 2015), and the baseline data of participants were extracted from the CHARLS wave 1(in 2011), excluding those with depressive symptoms in 2011 and forming a longitudinal cohort from 2011 to 2015. Logistic multiple regression was performed to investigate the cross-sectional and longitudinal associations of SUA with depressive symptoms in the two cohorts. Furthermore, we performed two-sample Mendelian randomization analyses to explore the potential causal relationships between them.

We included two cohorts of 9056 and 3177 individuals respectively. Logistic regression showed that individual with higher SUA levels had a lower risk of depressive symptoms (OR = 0.921; 95%CI: 0.886-0.957) in the cross-sectional cohort. However, neither the baseline SUA level (OR = 1.055, 95%CI: 0.961-1.157) nor the change in SUA level (OR = 0.945, 95%CI: 0.656-1.363) affected the depressive symptoms 4 years later in the longitudinal cohort. The two-sample MR showed that there was no genetic causal relationship between SUA and depression (OR_{IVW_MRE}= 1.071, 95% CI: 0.926-1.238).

SUA and depressive symptoms are associated, with lower SUA levels observed in middle-aged and older participants with depressive symptoms; however, no causal evidence supports their relationship.