Low Morning Cortisol in CFS

Below is another new study showing decreased morning adrenal cortisol and elevated evening cortisol levels in CFS (which suggest an alteration in day/night rhythms and which would also disrupt sleep). This is on the heels of a recent study showing low morning cortisol in women with CFS and an excellent review article by Dr. Kent Holtorf on the need for and safety of adrenal support in CFS. For a summary of Dr. Holtorf's article see "Adrenal problems in CFS."

Published online before print March 31, 2008
Psychosom Med 2008, doi:10.1097/PSY.0b013e3181651025
Alterations in Diurnal Salivary Cortisol Rhythm in a Population-Based Sample of Cases With Chronic Fatigue Syndrome

Urs M. Nater, PhD, Laura Solomon Youngblood, MPH, James F. Jones, MD, Elizabeth R. Unger, MD, PhD, Andrew H. Miller, MD, William C. Reeves, MD, MSc, Christine Heim, PhD

Address correspondence and reprint requests to: William C. Reeves, MD, MSc, E-mail: wcr1@cdc.gov.

Abstract

Objective: To examine diurnal salivary cortisol rhythms and plasma IL-6 concentrations in persons with chronic fatigue syndrome (CFS), persons not fulfilling a diagnosis of CFS (we term them cases with insufficient symptoms or fatigue, ISF) and nonfatigued controls (NF). Previous studies of CFS patients have implicated the hypothalamic–pituitary–adrenal axis and the immune system in the pathophysiology of CFS, although results have been equivocal.

Methods: Twenty-eight people with CFS, 35 persons with ISF, and 39 NF identified from the general population of Wichita, Kansas, were admitted to a research ward for 2 days. Saliva was collected immediately on awakening (6:30 AM), at 08:00 AM, 12 noon, 4:00 PM, 8:00 PM and at bedtime (10:00 PM) and plasma was obtained at 7:30 AM. Salivary cortisol concentrations were assessed using radioimmunoassay, and plasma IL-6 was measured using sandwich enzyme-linked immunosorbent assay.

Results: People with CFS demonstrated lower salivary cortisol concentrations in the morning and higher salivary cortisol concentrations in the evening compared with both ISF and NF groups indicating a flattening of the diurnal cortisol profile. Mean plasma IL-6 concentrations were highest in CFS compared with the other groups, although these differences were no longer significant after controlling for BMI. Attenuated decline of salivary cortisol concentrations across the day and IL-6 concentration were associated with fatigue symptoms in CFS.

Conclusions: These results suggest an altered diurnal cortisol rhythm and IL-6 concentrations in CFS cases identified from a population-based sample.