The role of cortisol and alpha-amylase in stress induced pain in fibromyalgia patients
Researchers from the University of Marburg, Germany recently studied how stress affects women with fibromyalgia syndrome (FMS). Fibromyalgia Syndrome refers to widespread muscle pain, tenderness to palpation and incapacitating fatigue that cannot be explained by any medical conditions. Although symptoms are usually stable, there are evidences suggesting that stress can exacerbate and perpetuate FMS pain.
In this work, scientists investigated the relationship between stress and pain in fibromyalgia patients without major depression disorders. Authors also examined whether the hypothalamic-pituitary-adrenal axis (cortisol) and autonomic nervous system (salivary alpha-amylase), two major stress-related systems, played a role in the development of this relationship.
The study consisted of a 14 day ambulatory assessment study of 32 FMS female patients between 18 and 65 years of age. Only female patients were considered due to the higher impact of FMS in women and also to avoid known discrepancies in pain evaluation between males and females. Participants provided six daily entries on momentary stress and pain levels, which were accompanied by simultaneous saliva collections to determine cortisol and alpha-amylase levels indicatives of the hypothalamic-pituitary-adrenal axis and the autonomic nervous system, respectively.
The results showed that stress is associated with a higher pain level, although the opposite is not true. However, they did not find a connection between alpha-amylase (or autonomic nervous system function) and pain intensity. Nonetheless, the authors found a correlation between cortisol levels and pain within one hour of awakening suggesting that cortisol might contribute for the diurnal fluctuation of FMS symptoms.
The researchers concluded that stress is an important exacerbating factor for pain in FMS patients and a potential contributor of pain perpetuating in these patients. Thus, more research is needed to determine whether these findings might mirror underlying fibromyalgia pathology.