Sleep duration and - quality in patients with diabetes mellitus type 1

Type 1 diabetes mellitus (DM1) is due to destruction due of pancreatic β-cell
which results in absolute insulin deficiency. Intensive treatment is essential
in DM1 for optimal glucoregulation, because the complications are determined by
the degree of long term hyperglycemia. Although novel treatment strategies,
including more physiological insulin replacement therapies have been developed,
glucoregulation can still not be normalized in patients with DM1. This is
reflected in relatively large variations in blood glucose levels and relatively
high HbA1c levels compared to healthy subjects. There are unexpected variations
in glucoregulation in these patients on a day to day basis.
In healthy individuals, plasma glucose homeostasis results from a tightly
controlled balance between glucose production and glucose utilization, in which
variations in insulin secretion play a key role. Normal glucose regulation
shows a 24h circadian rhythmicity with variations in insulin secretion. In
contrast, DM1 patients cannot compensate these variations in glucose tolerance
by subtle changes in endogenous insulin secretion.

Increasing evidence exists for an important role of sleep in diurnal variations
in glucose metabolism. Recently, attention has been focussed on the
pathofysiological effects of sleep loss on glucose metabolism and endocrine
function. Sleep loss and decreased quality of sleep impair glucose tolerance
and insulin sensitivity, even in healthy individuals.

A recent study in patients with DM1 demonstrated decreased sleep quality
compared to healthy controls and also complaints of fatigue and numbness were
more seen in patients with DM1. We postulate that disturbed sleep duration
and/or - quality in an important physiological determinant of glucoregulation
in DM1. If patients with DM1 have an altered sleep duration and/or -quality ,
sleep could be one of the important physiological determinants of
glucoregulation in DM1.

• To determine the sleep pattern in patients with DM1 with validated
questionnaires with a special focus on sleep
duration, - quality and daytime sleepiness.

• To investigate the association between sleep parameters and glucoregulation
(HbA1c), we will compare:
* Moderate/poor controlled patients (HbA1c > 7.5 %
with/without organ damage) vs. well-controlled patients
(HbA1c < 7.5% without organ damage)
* Well-controlled patients (HbA1c < 7.5% without organ
damage) vs. healthy controls

• To determine vigilance during the day we will perform two Sustained Attention
to Response Task (SART)

All patients who visit the DM outpatient clinic of the LUMC and meet the
inclusion criteria will be asked to participate in this study. Subjects will be
given oral explanation about the study by the investigator. When they give
their informed consent, they will be asked to fill out the questionnaires about
their habitual sleep duration, - quality and the existence of a possible
sleeping disorder. Consequently, we will perform twice a Sustained Attention to
Response Task (SART). In this test, participants are asked to respond to
numbers on a computer screen during 4 minutes to test their vigilance.

We will contact the well-controlled patients with DM1 and ask them to identify
someone in their group of acquaintances as a control who will fill out the
questionnaires. Controls will be targeted to be of the same sex, around the
same age and having about the same BMI as the patient, and not suffering from
DM. These controls will be invited to come to our hospital to fill out the
questionnaires and to perform twice a SART to test their vigilance.

The subjects will be asked to fill out 3 questionnaires about their habitual
sleep duration, - quality and the existence of a possible sleeping disorder.
Consequently, they are asked to perform twice a Sustained Attention to Response
Task. The study will take appoximately 3 hours.