Is there an association between fibromyalgia and below-normal levels of urinary cortisol?

Silvia Izquierdo Alvarez , Julia Pilar Bocos Terraz , Jose Luis Bancalero Flores , Lenin Pavon Romero , Enrique Serrano Ostariz and Cayetano Alegre de Miquel
BMC Research Notes 2008, 1:134
Published: 22 December 2008
Abstract (provisional)

Adynamia in fibromyalgia (FM) may be an expression of a functional deficit of the hypothalamic-pituitary-adrenal axis and be associated with below-normal levels of urinary cortisol. Our aim was to demonstrate that urinary cortisol was lower in patients with FM than in healthy subjects.

We measured urinary cortisol levels for a sample of 47 women aged 29 to 64 years (mean age 53 years), diagnosed with FM 2-3 years previously, and compared the results with those for a control sample of 58 healthy women of a similar age. Samples of 24-hour urine were appropriately collected and levels of urinary cortisol were measured using the fluorescence polarization immunoassay method. The mean cortisol value for the women with FM was 65.40+/-27.10 microg/L, significantly lower than the mean cortisol level for the control group, at 90.83+/-38.17 microg/L (p < 0.001).

Our study confirms that women with FM have significantly lower urinary cortisol levels than healthy women.

From the full study


Information on 24-hour urine cortisol levels does not constitute useful information in itself, but may be valuable when combined with other clinical tests normally performed to diagnose FM. Although a dysfunctional hypothalamic-pituitary-adrenal axis can lead to decreased sensitivity and resiliency in the stress system, it does not necessarily affect baseline cortisol levels, so 24-hour urinary cortisol levels alone cannot be used to evaluate FM. Urinary cortisol is a potentially useful biochemical marker in terms of evaluating adynamia in FM, along with insulin-like growth factor 1, substance P and the terminal telopeptides [20]. Nonetheless, studies based on larger samples are necessary in order to corroborate these conclusions.