In the overall population, the associations between the PON1 L55M genetic polymorphism and T2DM did not reach statistically significant under the allelic genetic model (OR = 0.91, 95% CI = 0.81–1.02; P = 0.118), homozygous genetic model (OR = 0.92, 95% CI = 0.69–1.23; P = 0.577) and recessive genetic model (OR = 1.05, 95% CI = 0.81–1.35; P = 0.729). The gene discussed is PON1; the disease is type 2 diabetes mellitus.