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. This evidence concerns the gene PTPN22 and diabetes mellitus.