Association between atherogenic index of plasma and depression risk: a meta-analysis

Background Lipid metabolism disorders have been implicated in the pathogenesis of depression. The atherogenic index of plasma (AIP), calculated as log(triglyerides/high-density lipoprotein cholesterol), is a convenient marker reflecting lipid profiles and cardiovascular risk. However, the relationship between the AIP and depression remains unclear. Methods Relevant observational studies were identified through comprehensive searches of the PubMed, EMBASE, and Web of Science databases. Studies were included if they reported AIP values and diagnosed depression using standardized assessment tools. A total of 10 observational studies, encompassing 38,785 participants, were included. Subgroup analyses were conducted to assess the impact of age and diagnostic criteria on the association. Heterogeneity was assessed using the I² statistic, and publication bias was evaluated using funnel plots and Egger’s test. Results Individuals with depression had significantly higher AIP values compared with healthy controls (mean difference = 0.07; 95% confidence interval: 0.03–0.11; P = 0.0006). High heterogeneity was observed ( I² = 94%, P < 0.00001). The funnel plot showed slight asymmetry; however, Egger’s test indicated no significant publication bias ( P = 0.354). Sensitivity analyses confirmed the robustness of the findings. Conclusion Higher AIP values are associated with an increased risk of depression, particularly in individuals aged ≥50 years. Given its accessibility, the AIP may serve as a useful biomarker for the early identification of individuals at risk for depression. The quantification of the overall association between AIP and depression risk represents a novelty of this study and highlights AIP as an integrative lipid biomarker with potential predictive value beyond single lipid indices. Prospective studies are needed to confirm causality and explore the underlying biological mechanisms. Systematic review registration https://www.crd.york.ac.uk/prospero/ , identifier CRD420251035701.