Association between apolipoprotein E gene polymorphism and depression

We performed an updated meta-analysis to obtain a more precise estimation of the relationship between apolipoprotein E (ApoE) gene polymorphism and susceptibility to depression, as previous reports have been inconsistent. Twenty studies with 2286 depression patients and 3845 controls were included. Odds ratios (OR) with 95% confidence intervals (CI) were calculated to assess the association between ApoE gene polymorphism and depression using a random effects model. Results showed a significant association between ApoE gene polymorphism and susceptibility to depression in the overall population (epsilon 2/epsilon 3 genotype versus epsilon 3/epsilon 3: OR 0.76, 95% CI 0.59-0.99). Subgroup analyses indicated an association in the Caucasian population (epsilon 2 allele versus epsilon 3: OR 0.75, 95% CI 0.58-0.97) as well as in late-life depression (LLD) patients (epsilon 3/epsilon 4 genotype versus epsilon 3/epsilon 3: OR 1.34, 95% CI 1.07-1.68, and epsilon 4 allele versus epsilon 3: OR 1.30, 95% CI 1.06-1.59). We concluded that the epsilon 2/epsilon 3 genotype likely provided a protective effect against depression in the overall population and the epsilon 2 allele acted as a protective factor for depression in the Caucasian population while the epsilon 4 allele and epsilon 3/epsilon 4 genotype were associated with an increased risk of depression in the LLD subjects. (C) 2015 Elsevier Ltd. All rights reserved.