Additionally, in the T2DM+obesity group, reduced AAT (OR=0.997, P<0.05, 95%CI:0.996–0.998) and increased C3 (OR=7.202, P<0.01, 95%CI:2.643–19.626) and α2-MG (OR=16.801, P<0.01, 95%CI: 7.401–38.13) levels were found to influence T2DM development. The gene discussed is SERPINA1; the disease is type 2 diabetes mellitus.