MMP9 and diabetic kidney disease: The MMP9-1562 C/T genotype was significantly associated with the risk of diabetic nephropathy after stratification by specific type of microvascular complication (CT + TT vs. CC: OR = 0.42, 95% CI = 0.26–0.69, p = 0.0006; TT vs. CC + CT: OR = 0.37, 95% CI = 0.19–0.76, p = 0.006).