Depression and serum low-density lipoprotein: A systematic review and meta-analysis

•Continuous studies show lower mean serum LDL in depression.•Categorical studies show marginally significant lower odds of depression in lower serum LDL.•Discordant findings may suggest a U-shaped relationship between depression and LDL.•Prospective analyses are needed to clarify the role of temporality.

BackgroundA cross-sectional association between depression and serum low-density lipoprotein (LDL) has been noted in the literature. This study aims to employ meta-analytic techniques to clarify the relationship between depression and serum LDL.MethodsPublished articles through April 2015 were identified through systematic query of PubMed with follow-up manual searches. Data from 36 studies reporting mean difference and 7 studies reporting odds ratios were analyzed separately.ResultsMeta-analysis of studies modeling serum LDL as a continuous measure demonstrates overall significantly lower serum LDL in depression (Mean difference=−4.29, 95% CI=−8.19, −0.40, p=0.03). Meta-analysis of studies modeling serum LDL as a categorical measure demonstrates a marginally significant lower odds of depression in the presence of low serum LDL relative to high serum LDL (OR=0.90, 95% CI=0.80, 1.01, p=0.08).LimitationsHigh heterogeneity was noted across sampled studies, which may be a function of variations in study design, participants sampled, or other factors. The potential for publication bias was also assessed.ConclusionsThis meta-analysis demonstrates a cross-sectional link between depression and low serum LDL.