CCL2 and type 2 diabetes mellitus: Further, CCL2 concentrations were compared between 3,856 T2DM patients and 2,958 controls, and the results indicated that CCL2 concentrations were in patients with T2DM than in the controls (SMD=1.51; 95% CI: 1.15 - 1.88; Figure 1), but with significant heterogeneity (I2=97%).