In general terms, hormone therapy refers to the use of hormone-containing medications to replace hormones that the body no longer produces on its own. The most widely-known use of hormone therapy is arguably that which is used as treatment for the myriad symptoms associated with menopause. This type of hormone therapy usually involves taking supplements of the female sex hormones estrogen and progesterone. Long-term use of such therapy was common in standard medical practice until the summer of 2002, when findings from a large clinical trial were published that showed women who took such therapy had an increased risk for heart disease, breast cancer, stroke, and blood clots (WHI, 2002). As a result, the long-term use of hormone therapy to prevent postmenopausal symptoms is no longer widely advocated; however, short-term use of estrogen (without progesterone) may help to protect some women against osteoporosis, colorectal cancer, and heart disease, and is still used to treat various menopausal symptoms in women for whom the benefits outweigh the potential risks (Mayo Clinic, 2010).
On a broader scale, the term “hormone therapy” can also be used to describe any type of supplemental hormone replacement therapy for individuals who experience a particular hormone deficiency. For example, individuals with hypothyroidism have insufficient production of thyroid hormone, and as a result can be considered thyroid hormone-deficient. Subsequent treatment with synthetic thyroid hormone supplements would also be considered, by definition, to be hormone therapy.
The Relationship between Hormones and Fibromyalgia
A number of possible hormones have been investigated in terms of their relationship to fibromyalgia, both in terms of deficiency and as a means of fibromyalgia therapy. These include growth hormone, melatonin, estrogen/progesterone, and cortisol.
As many of 50% of all fibromyalgia patients have abnormalities in various growth hormones (Cuatrecasas et al., 2012), however the significance of these findings is not fully understood. It has been noted that the areas of the brain that process growth hormone signals are also the same areas that process and regulate pain sensations (Cuatrecasas et al., 2012), and that typical growth hormone responses to exercise are often impaired in fibromyalgia patients (Ross et al., 2010).
Melatonin is another hormone that has received considerable attention by the research community for its role in fibromyalgia. This is primarily due to melatonin’s role in the regulation of normal sleep-wake patterns, and the fact that so many fibromyalgia patients experience disrupted and non-refreshing sleep. Some studies have found lower levels of melatonin during the evening hours among fibromyalgia patients, (Wikner et al., 1998; Mahdi et al., 2011), whereas others have not (Senel et al., 2011).
Research into the relationship between sex hormones and fibromyalgia has also gained momentum in recent years. Recent study findings suggest that the female menstrual cycle may play a role in the exacerbation or “flaring up” of fibromyalgia symptoms (Colangelo et al., 2011; Martin, 2009), suggesting that variations in levels of estrogen and/or progesterone may somehow influence fibromyalgia. These findings are in contrast to earlier studies that found little if any association between sex hormones and fibromyalgia (Korszun et al., 2000; Okifuji & Turk, 2006), or with generalized widespread pain (Macfarlane et al., 2002). However, other studies investigating the possible biological links between sex hormones and fibromyalgia have suggested that they may be directly related to inflammation and stress responses, as well as to pain regulation and reactivity (Martin, 2009). Therefore, the association between sex hormones and fibromyalgia remains an important topic of interest.
Cortisol is a steroid hormone produced naturally by the adrenal gland. It is often referred to as the “stress hormone,” as it is released in excess as part of the body’s natural response to stress. The production of cortisol has been shown to be compromised in individuals with fibromyalgia (Izquierdo-Alvarez S, et al., 2008; Griep et al., 1998; Lentjes et al., 1997). In addition, decreased cortisol has also been linked to reduced exercise tolerance, muscle fatigue, mood swings, sleep disturbances, and depression (Cleare et al., 2001; Gur et al., 2004), all of which are common symptoms and conditions associated with fibromyalgia.
Hormone Therapy and Fibromyalgia
The majority of the research regarding hormone therapy for fibromyalgia centers around therapy with growth hormones, as well as melatonin. Very limited research has been conducted with regard to estrogen therapy and fibromyalgia.
Bennett and colleagues have provided evidence to suggest that therapy with growth hormones is both effective and tolerable (Bennett et al., 1998). Cuatrecasas and colleagues have built on these findings with their own contributions. They conducted a pilot study in 2007 to further investigate the effectiveness and safety of growth hormone therapy in fibromyalgia patients. Of the 24 patients included in this study, those treated with growth hormone showed a 60% reduction in the average number of tender points when compared to those who received a placebo therapy (Cuatrecasas et al., 2007). A larger and more recent study by the same group evaluated the effectiveness and safety of growth hormone therapy in 120 fibromyalgia patients over an 18 month period. All patients received either hormone therapy or placebo therapy in addition to their standard therapies, which included antidepressants and opioid pain medications. Pain intensity and overall functioning were also assessed. After completion of the study, the researchers found that those who received growth hormone therapy had significantly improved pain severity than those who received placebo. Furthermore, although discontinuation of therapy during the follow-up period resulted in increased pain, those who had received the growth hormone therapy reported less-pronounced pain perception during that time (Cuatrecasas et al., 2012).
Hormone therapy using melatonin has also been investigated as a means of treating fibromyalgia. Citera et al., found improvements in pain, sleep, and a variety of other common fibromyalgia symptoms, however the small sample size in their study and potential flaws in its design decrease the impact of their findings (Citera et al., 2000). Hussain et al. also found that melatonin therapy was beneficial at improving pain in fibromyalgia patients when taken either alone, or in combination with the antidepressant fluoxetine (Prozac). Read more about Melatonin for Fibromyalgia.
One small study regarding the use of estrogen therapy as a treatment for fibromyalgia has been conducted. This randomized, placebo-controlled trial (considered the ‘gold standard’ for research study design) lasted for eight weeks, and evaluated the effectiveness of supplemental estrogen therapy delivered via skin-patches on self-perceived pain in 29 post-menopausal fibromyalgia patients. At the conclusion of the study, the women who received estrogen therapy experienced significantly increased levels of estrogen over the duration of the study, which was an expected finding. However, the study showed no differences in self-reported measures of pain perception, threshold, or tolerance between the women who received the estrogen and those who received placebo treatment (Stening et al., 2011).