Biological stress activity in obese children compared to normal weight controls: a pilot study.

Our society has seen major structural changes in the last 20 years such as
technological advancements. These changes have been affecting working patterns,
social networks, and family structures. As a result of this, levels of stress
have increased in society. Recently a third of children in a general population
study were found to experience increased stress. Psychological stress is
communicated to the body by activation of the physical stress system, with
elevation of the stress hormone (cortisol) as a key mediator. Extended periods
of elevated cortisol (such as in diseases like Cushing syndrome) or
pharmacologic treatment with synthetic cortisol (like prednisone) lead to
obesity, and its metabolic sequelae. Recent studies provide evidence for the
relationship between chronic stress and obesity in monkeys and human adults. No
studies have been performed in children yet.

The objective of this study is to analyse the association between stress and
obesity in children. We hypothesize that obese children have higher levels of
stress than normal weight controls. The key objective is to study differences
in stress levels in obese children as compared to normal weight controls. In
addition, we aim to study the association between genetic sensitivity to
cortisol and obesity in childhood.

In this pilot study, 10 children with obesity and 10 normal weight controls in
the age range 8-12 years will be enrolled after informed consent. Exclusion
criteria are presence of a chronic disease, use of corticosteroids or
beta-blockers. Data on basic characteristics and anthropometric parameters will
be collected. Participants will complete questionnaires about stress
perception, coping, reward sensitivity, food craving and eating behaviour.
Cortisol level in a small sample of hair, cut from the back of the head (± 100
hairs) will be obtained as a marker for chronic stress. Daily stress will be
measured using salivary cortisol; six salivary samples are obtained on 1 day.
Salivary sampling will be performed at home after detailed instruction. The
saliva samples will be sent to the hospital by mail. The very-low-dose (0.25
mg) dexamethasone suppression test will also be performed at home. Participants
will take 0.25 mg dexamethasone (adjusted to bodyweight; 3.33 microgr/kg) at
bedtime. The next morning post-dexamethasone cortisol is measured in saliva
(7th salivary sample). The post-dexamethasone cortisol level will be used as a
measure of cortisol sensitivity.

Dexamethasone suppression test (see study design)

There are no risks associated with participation in this study. The dose of
dexamethasone is so low that no side effects are expected. This study has no
burden, only time investment can be called a burdening. In this study only
patient- and childfriendly investigations are used.