A systematic review and meta-analysis of lipid metabolomic signatures of Major Depressive Disorder

The aim of this meta-analysis was to provide a comprehensive synthesis of the evidence examining biomarker signatures in MDD patients including lipids, lipid regulatory proteins (LRP), and polyunsaturated fatty acid (PUFA) as compared to healthy individuals. We performed meta-analyses and meta-regression of the studies comparing lipid, LRP, and PUFA levels between MDD patients and healthy individuals by searching Embase, Ovid Medline, Scopus, PsycINFO, PubMed, and Cochrane databases. Search was performed in these databases up to September 2019 and 29 studies were included. Levels of lipid parameter triglyceride (TG) (SMD 0.55, 95% CI 0.30-0.80, p < 0.0001) were higher while total cholesterol (TC) (SMD = -0.46, 95%CI -0.93 to -0.001, p = 0.04) and very low-density lipoprotein (VLDL) (SMD = -0.46, 95%CI -0.71 to -0.20, p = 0.02) were lower in MDD patients than controls. Subgroup analysis for age showed that the levels of high-density lipoprotein (HDL) were lower in ≥40-year age group (SMD = -0.38, 95%CI -0.70 to -0.06, p = 0.01) and levels of TC was lower in MDD patients in studies from Asian countries (SMD = -0.74, 95%CI -1.37 to -0.10, p = 0.02). TG levels were found to be high all subgroups in MDD patients than controls. A negative association between TC levels and use of lipid lowering medications and a positive association between smoking and LDL levels was found using meta-regression analysis. This study will be useful for physicians when considering the assessment of lipidand LRP profiles in MDD patients to reduce the cardiovascular morbidity and mortality.