In the unadjusted model and Model I, which minimally adjusted for several variables, each 1 g/L increment in Hb was significantly inversely associated with developing depression (non-adjusted: OR = 0.92, 95% CI: 0.87, 0.97; model I: OR = 0.92, 95% CI: 0.86, 0.98). Here, GSTM1 is linked to major depressive disorder.