Blood cell biomarker trajectories and depression risk in a sex-stratified 10-year longitudinal cohort analysis

Depression is a global health challenge, and recent attention has been given to the influence of hematological biomarkers in predicting its onset. In this study, we assessed the relationship between 32 blood cell-related biomarkers and depression risk among 87,493 participants (45.9% female; mean age at baseline 43.47 years, s.d. 10.59) with repeated measures over a median follow-up of 2 years (range 1–8 years) from a population-based cohort, the West-China Hospital Alliance Longitudinal Epidemiology Wellness Study. Adjusted Poisson regression models revealed significant associations between lymphocyte biomarkers (CD4, CD8 and ratios) and depression risk (all false discovery rate <0.05). Red-cell distribution width was significantly associated with depression in female participants (adjusted risk ratio 1.171, 95% confidence interval 1.063–1.29, false discovery rate 0.013). Trajectory analysis, using latent class mixed modeling, revealed that monocyte-to-lymphocyte ratio and neutrophil-to-lymphocyte ratio trajectories were found to be predictive of depression, with monocyte-to-lymphocyte ratio and lymphocyte count patterns particularly associated with increased risk among male participants. These findings provide insights into the role of sex-specific hematological biomarker trajectories in depression risk, emphasizing the need for further exploration of targeted prevention and intervention strategies based on biomarker patterns. Wang et al. analyzed data from a large population-based cohort study in China to examine the relationship between blood cell biomarkers and the risk of depression.