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Fibromyalgia Research: Hypothalamic-Pituitary-Adrenal Stress

Axis Function and the Relationship with Chronic Widespread

Pain ImmuneSupport.com

10-12-2005

Arthritis Res Ther. 2005;7(5):R992-R1000. Epub 2005 Jun 17.

McBeth J, Chiu YH, Silman AJ, Ray D, s R, Dickens C, Gupta A,

Macfarlane GJ.

Arthritis Research Campaign (ARC) Epidemiology Unit, School of Epidemiology

and Health Sciences, University of Manchester, Manchester, United Kingdom.

john.mcbeth@....

ABSTRACT : In clinic studies, altered hypothalamic-pituitary-adrenal (HPA)

axis function has been associated with fibromyalgia, a syndrome

characterised by chronic widespread body pain. These results may

be explained by the associated high rates of psychological distress

and somatisation. We address the hypothesis that the latter, rather

than the pain, might explain the HPA results.

A population study ascertained pain and psychological status in subjects

aged 25 to 65 years. Random samples were selected from the following

three groups: satisfying criteria for chronic widespread pain; free of

chronic widespread pain but with strong evidence of somatisation

('at risk'); and a reference group.

HPA axis function was assessed from measuring early morning

and evening salivary cortisol levels, and serum cortisol after

physical (pain pressure threshold exam) and chemical (overnight

0.25 mg dexamethasone suppression test) stressors. The

relationship between HPA function with pain and the various

psychosocial scales assessed was modelled using appropriate

regression analyses, adjusted for age and gender.

In all 131 persons with chronic widespread pain (participation rate 74%),

267 'at risk' (58%) and 56 controls (70%) were studied. Those in the

chronic widespread pain and 'at risk' groups were, respectively, 3.1

(95% CI (1.3, 7.3)) and 1.8 (0.8, 4.0) times more likely to have a saliva

cortisol score in the lowest third. None of the psychosocial factors

measured were, however, associated with saliva cortisol scores.

Further, those in the chronic widespread pain (1.9 (0.8, 4.7)) and

'at risk' (1.6 (0.7, 3.6)) groups were also more likely to have the highest

serum cortisol scores.

High post-stress serum cortisol was related to high levels of

psychological distress (p = 0.05, 95% CI (0.02, 0.08)). After

adjusting for levels of psychological distress, the association

between chronic widespread pain and post-stress cortisol

scores remained, albeit slightly attenuated. This is the first

population study to demonstrate that those with established,

and those psychologically at risk of, chronic widespread pain

demonstrate abnormalities of HPA axis function, which are

more marked in the former group.

Although some aspects of the altered function are related to

the psychosocial factors measured, we conclude that the

occurrence of HPA abnormality in persons with chronic

widespread pain is not fully explained by the accompanying

psychological stress.