The interaction of miR-34b/c polymorphisms and negative life events increases susceptibility to major depressive disorder in Han Chinese population.

•The significance of miR-34b/c gene polymorphisms in MDD was evaluated.•The rs4938723 and rs2187473 polymorphisms were associated with stratified MDD by discarding subjects with severe negative life events in the dominant models.•C-G haplotype (rs4938723/rs28757623) showed the strongest association with stratified MDD.•Significant gene–environment interaction between the C-G haplotype (rs4938723/rs28757623) and negative life events associated with MDD risk.