Reply to comment on: Godsland IF, Jeffs JA, Johnston DG (2004) Loss of beta cell function as fasting glucose increases in the non-diabetic range. Diabetologia 47:1157–1166

Excerpt

To the Editor: As we stated in our original paper [1], our intention was to define the level of glycaemia at which pancreatic insulin secretion begins to decline. We were careful throughout to emphasise that we were concerned not with causal relationships but with identifying the principal accompaniments of deteriorating fasting plasma glucose (FPG) levels in the sub-diabetic range. We agree with Abdul-Ghani and DeFronzo that the decline in IVGTT first-phase insulin secretion that accompanies the rise in FPG does not necessarily indicate a causal relationship [2]. Nevertheless, in our study, the decline in first-phase pancreatic insulin secretion was by far the most striking feature that accompanied increasing glucose levels. As Abdul-Ghani and DeFronzo affirm, the important aspect of this decline was that it occurred within ranges of glucose concentrations hitherto considered normal. …