The magnitude of the disturbance of metabolic control in diabetes mellitus in very young children has been recognised, but seldom studied. Limitations to studies are set by the difficulty of obtaining control data and until recently the lack of alternative therapies. Recently "mini" pumps for continuous subcutaneous insulin delivery have become available and may offer an alternative therapeutic possibility. The present investigation has been undertaken to collect overnight metabolic data of very young diabetic children (< 6 years) controlled by standard injection therapy. During one admission to hospital frequent blood samples were collected for free insulin, glucose, alanine, lactate, glycerol and 3-hydroxybutyrate determinations. In all children (n = 9) the profiles showed a steep rise in glucose from 04.30 h (6.2 + 1.3 mmol/1) to 09.30 h (17.8 + 2.4 mmol/1) (the so-called "dawn-phenomenon"). The nature of the changes in the intermediary metabolites suggested that rise in blood glucose was caused by insufficient insulin. We have attempted to explore the time relationship between the overnight drop in free insulin levels and the rises in blood glucose by a distribution-free statistical analysis, correlating successive changes in time between the two profiles. The analysis suggested a delay of 2-6 h between free insulin levels and their effects.
In conclusion: a clear "dawn phenomenon" is seen in very young diabetic children, and contributes to their poor glycaemic control. More stable and higher insulin concentrations in the early morning, obtained perhaps by continuous subcutaneous insulin infusion, might ameliorate the overall glycaemic control in the very young diabetic child.