Hair cortisol level in children with and without asthma

Children with asthma have significant lower salivary cortisol levels than their
healthy counterparts. Measurement of cortisol levels in saliva is attractive
since it is non-invasive. Time of saliva collection, medication, food, stress
and infection may affect cortisol levels in saliva. Recently it has been
demonstrated in adults that longitudinal cortisol levels can be measured in
hair. In children this has never been studied. We want to evaluate the
feasibility of cortisol measurement in hair samples in children and also to
determine whether cortisol levels in hair give better insight in the effect of
chronic inhaled corticosteroid use on the pituitary-adrenal axis.

1 To evaluate the feasibility to measure cortisol levels in hair in healthy
children and children with asthma who use inhaled corticosteroids

2 To evaluate differences in cortisol levels in hair in healthy children and
children with asthma who use inhaled corticosteroids

3 To evaluate the correlation between single measurement of salivary cortisol
levels and cortisol levels in healthy children and children with asthma who use
inhaled corticosteroids

Observational

The investigator will visit the children at home to collect a hair sample and
give information about the collection of a saliva . The children with asthma
will also perform lungfunction. This visit will take approximately 30 minutes.
The next morning the children will chew on a cotton wool swab for 1 to 2
minutes and mail this saliva sample to the hospital. There are no visits to the
hospital.


We don not expect any risks for the participants