However, MC4R-rs6567160 could increase the occurrence of T2DM among nonsmokers under the codominant (OR = 1.60, 95% CI = 1.04–2.45, p = 0.032) and dominant (OR = 1.56, 95% CI = 1.04–2.34, p = 0.031) models. Here, MC4R is linked to type 2 diabetes mellitus.