Association of TNF-alpha G-308A gene polymorphism with depression: a meta-analysis

Background: Although many studies have investigated the association of a single nucleotide polymorphism in TNF-alpha G-308A gene with depression, their association is still controversial. To clarify this, we performed a meta-analysis. Method: Studies related to TNF-a G-308A and depression were retrieved from PubMed, Medline, Embase, and Scopus (up to April 18, 2017). The odds ratios (ORs) and 95% confidence intervals (CIs) were estimated in the models of allele comparison (G vs A), homozygote comparison (GG vs AA), dominant (GG vs GA + AA), and recessive (GG + GA vs AA) to estimate the strength of the associations. Results: A total of 10 case-control studies were included in this meta-analysis. Overall, no significant association between TNF-alpha G-308A and depression was found (G vs A: OR [95% CI] = 1.09 [0.92, 1.29]; GG vs AA: 1.24 [0.71, 2.15]; GG vs GA + AA: 1.01 [0.76, 1.35]; GG + GA vs AA: 1.22 [0.70, 2.13]). In subgroup analyses by ethnicity or age group, no statistically significant association between TNF-alpha G-308A polymorphisms and depression was shown. Conclusion: This meta-analysis revealed that TNF-alpha G-308A polymorphism is not associated with susceptibility to depression.