INS and type 2 diabetes mellitus: Transferrin, soluble transferrin receptor (sTfR), transferrin saturation (TSAT), sTfR-to-log10ferritin (sTfR-F) index and iron with impaired glucose metabolism/prediabetics, T2DM and insulin traits were investigated in 2893 participants in a population-based cooperative health research in the region of Augsburg (KORA) F4 study in Germany.