GSTM1 and type 2 diabetes mellitus: In patients with type 2 diabetes, serum Zn/Cu ratio was positively correlated with height (r = 0.178, p = 0.031), serum levels of Alb (r = 0.46, p < 0.001), Hb (r = 0.41, p < 0.001), and Ht (r = 0.277, p = 0.016) and negatively correlated with age (r = −0.223, p = 0.006), plasma HbA1c levels (r = −0.193, p = 0.019) (Figure 1), and plasma BNP levels (r = −0.392, p = 0.022).