INS and type 2 diabetes mellitus: In our study, the largest group with impaired glucose regulation (Fig. 2) was the one with IGT, which is characterized by insulin secretion inadequate for the glucose load.20 Insulin secretion plays a central role in the development of T2D as most risk genes for T2D influence insulin secretion and not insulin resistance, and FFAs are known to influence insulin secretion.27 We did find higher fasting and 2-h FFA concentrations after a 75 g glucose dose in VLBW vs sibling participants.