Neuroendocrine consequences of sleep-disturbances in type 2 diabetes patients with and without depression

Depression and Diabetes are common disorders with a high impact on public
health. The relationship between depression and diabetes is complex, depresion
is asociated with increased risk of diabetes onset and depression is more
prevalent in patients with diabetes. Depression is associated with worse
glyceamic control in patients with diabetes, and also with increased risk of
diabetes complications and mortality. However, the pathophysiological
mechanism that may explain link is still unclear. Insomnia, which is prevalent
in about 70% of patients suffering from depression, and persists in about 25%
after remission of depression, negatively influences glycaemic control and
insulin sensitivity in diabetes, supposedly through the associated misalignment
of circadian variation in glucocorticoids and melatonin. Along this line of
reasoning, we hypothesize that the negative effects of depression on diabetes
are partly mediated by sleep problems and the underlying misalignment of the
circadian rythmicity of cortisol. This hypothesis has never been tested before.

The objective of this study is to investigate:
1) the prevalence of insomnia in patients with T2D with and without depression
2) whether insomnia in patients with T2D with and without depression, is
associated with increased levens of HbA1C
3) whether the presumed association between insomnia and increased HbA1C is
mediated by circadian misalignment of cortisol
Knowledge on the neuro-endocrinological mechanism underlying the
depression-diabetes relationship, can be used directly to develop more *tailor-
made* treatment programs for comorbid depression, such as Bright Light Therapy,
which can be used to reduce both the clinical syndrome as well as the
associated neuro-endocrine deregulation.

cross-sectional observational study

No risks associated with the study. 1 extra visit to the hospital, with max 2
to 3 hrs questionnaires, 1 venapunction 3 x 4 ml, wrist actomter during 1 week,
sleepdiary during 1 week, 1 day saliva monsters. No individual benefit apart
from 15 euro check and travel expenses. Benefit for the patient group: develop
more *tailor-made* treatment programs for comorbid depression, such as Bright
Light Therapy, which can be used to reduce both the clinical syndrome as well
as the associated neuro-endocrine deregulation.