Dawn Phenomenon - A condition some people with insulin-dependent diabetes experience resulting in a significant rise in their early morning blood glucose values (around 5:00 am), possibly requiring additional insulin to control. The incidence and severity of the dawn phenomenon has been debated since its discovery by Schmidt et al in 1981.

An Italian group has studied 114 subjects with Type I diabetes (none using a pump) on 3 separate occasions to assess their insulin requirements between midnight and morning. The results revealed 89% of the patients had an increased need for insulin during the dawn hours. This increase was only 20%, which was lower than previously reported.

The results were extremely reproducible on different days in the same patient. A more pronounced dawn phenomenon tended to occur in patients who were in poorer control, had a shorter duration of diabetes, had adequate counter-regulatory hormones, and used large amounts of insulin.

Dawn Phenomenon is associated with:

• Poor Control
• Short duration of diabetes
• Adequate counter-regulatory hormones
• High insulin needs

Perriello concludes his article with: "The dawn phenomenon is a very frequent event in subjects with Type I diabetes mellitus; its magnitude is lower than initially indicated; it is highly reproducible from day to day; it is influenced by factors such as, duration of diabetes, quality of antecedent glycemic control, state of counter-regulation system to hypoglycemia, and insulin sensitivity."

REFERENCES:

Perriello G et al.: The dawn phenomenon in type 1 (insulin-dependent) diabetes mellitus: Magnitude, frequency, variability, and dependency on glucose counterregulation and insulin sensitivity. Diabetologia 34:21-28, 1991