Cortisol output in adolescents with chronic fatigue syndrome: Pilot study on the comparison with hea

[Dolphin]

Chalder Fatigue Scale (Likert) (11-items)
Healthy Controls: 11.0 (IPQ: 10.3-12.8).

In the PACE Trial, 18 or less was claimed to represent normal fatigue.

 

[Dolphin]

The main thing it made me wonder is how much cortisol levels vary naturally and hence could there results be a result of natural variation or say additional stress of going back to a hospital for blood tests where you have had sessions saying 'you are not ill - you must push yourself'.

Cortisol was measured at home in a fairly non-invasive manner:

Procedure
The study was approved by the Institute of Psychiatry (King's
College London) Ethics Committee, reference 011/00.Written informed
consent was obtained from the young people and their parents. Questionnaire
completion and saliva collection was undertaken at home.
Participants were asked to collect the samples on a Saturday when
they were able to wake up between 6:00 a.m. and 09:00 a.m. Samples
were taken using untreated Salivettes. Participants were instructed to
provide a sample of saliva immediately after waking, 15, 30, 45 and
60 min after awakening, then at 12:00, 16:00 and 20:00 hours. Standard
collection instructions were given, e.g., not to eat or brush teeth in the
hour prior to collection. Participants were asked to note the time they
took the samples and what they had been doing the previous hour before
each sample, including anything eaten or drunk. Participants not
complying with the collection instructions were not included. Samples
were kept in the refrigerator overnight before being returned to the
hospital. Cortisol was measured for a second time at six months after
the end of treatment, to allow time for consolidation of the treatment
response and for any effects on the HPA axis to occur. The same saliva
collection procedure was used at Time 2.

 

[Dolphin]

Cortisol awakening response (CAR)
There were no significant differences between the two groups in terms of the area
under the curve with respect to the increase (AUCi) or with respect to the ground
(AUCg); see Table 1. Similarly, there were no group differences if participants were
excluded who scored 13 or above on the Birleson Depression Inventory or who were
taking medication that might affect cortisol. There were no significant correlations
between measures of CAR and questionnaire measures.

So there were plenty of null results.

As the authors say:

Analyses investigating the relationship between cortisol measures
and clinical variables were not adjusted for multiple testing due to the
exploratory nature of these investigations; this increases the risk of
false positives, so the findings require replication in future research.