In all modifiable risk factors, type 2 diabetes mellitus (T2DM) was an important environmental risk factor for PTB, and PTB incident was also influenced by gene- environment interactions, but to date, less study focused on the impact of PTPN22 gene SNPs, interaction between PTPN22 gene SNPs and T2DM on PTB susceptibility. The gene discussed is PTPN22; the disease is type 2 diabetes mellitus.