Arterial Stiffness in Type I Diabetes Mellitus
Arterial Stiffness in Type I Diabetes Mellitus
Using radial artery tonometry to study arterial stiffness, the plan is to study a cohort of
 65 children with Type I diabetes mellitus. This prospective, crossover study will help
 determine if there is an acute increase in arterial stiffness in children with Type I
 diabetes mellitus who do not give extra insulin to cover a meal. This will give more support
 to show why it is so critical to bolus every time they eat and to bolus on time to decrease
 cardiovascular consequences of poorly controlled diabetes. The hypothesis is that giving
 insulin before a meal compared to not giving insulin before a meal will be associated with
 lower arterial stiffness in children with type I diabetes.
The subject will fast overnight (nothing to eat or drink for at least 8 hours). The subject
 will be asked to drink a mixed meal replacement drink (Boost) and will be randomized (like
 flipping a coin) to bolus insulin for the "meal" or to not bolus insulin using their standard
 insulin dose. Glucose will be monitored with a finger prick before they drink the meal
 replacement, 1 hour later and finally 2 hours after drinking the meal replacement.

 Stiffness of the blood vessel of the wrist will be determined using radial tonometry. Radial
 tonometry is safe and does not hurt. A pen like probe is placed on the blood vessel of the
 wrist. When the machine reads a good wave form the computer will calculate the stiffness of
 the blood vessel. This test will be done along with the glucose checks; before drinking the
 meal replacement drink, and 1 and 2 hours after drinking the meal replacement drink.

 During the next study visit, the subject will repeat the exact same study described above.
 However, this time they will receive the other insulin assignment they were assigned during
 the first study (either bolus or no bolus).
Inclusion Criteria:

 -  Type 1 diabetes based on clinical history

 -  Basal-bolus insulin regimen

 -  Duration of diabetes greater than 1 year

 -  Blood glucose 65-200 mg/dL fasting

 Exclusion Criteria:

 -  Use of metformin or any other hypoglycemic agents besides insulin

 -  Use of anti-hypertensives

 -  Caffeine or smoking within the past 24 hours