Myofascial pain and fibromyalgia: Sleep quality and sex hormones in women with fibromyalgia

Abstract

Disturbed sleep is one of the prominent symptoms of fibromyalgia (FM). FM is more common in women, leading to a hypothesis that sex hormones may play a role in the pathophysiology of FM. We conducted a preliminary study to evaluate changes in sleep quality among women with FM across menstrual cycle. All participants were women (age 20-40) who had regular menstrual cycles and were taking no hormonal medications. Seven women with FM (by ACR criteria) and 8 healthy controls wore a Mini Motionlogger Actigraph for 30 consecutive days. The device provided continuous monitoring of activity level during waking hours and sleep quality during sleep at night. Blood was sampled across a cycle (mid-follicular, mid-luteal, and perimenstrual phases) to assess the levels of estradiol and progesterone. FM patients exhibited a significantly higher activity level during sleep compared to the control subjects. The analysis at each menstrual phase revealed that FM women exhibited longer sleep latency during the mid-follicular phase, higher activity during the sleep (i.e. restlessness) during the luteal phase, and longer sleep duration during the perimenstrual phase than did the controls. A series of correlational analyses revealed that the level of estradiol was generally negatively related to minutes spent asleep in FM women. However, the analysis by the menstrual phases showed significant phase effects on how estradiol level was related to the sleep parameters in FM. Consistently with the previous reports, women with FM seem to experience greater restlessness than healthy women during nighttimes. Furthermore, our results are suggestive of the significant hormonal influence on the sleep quality for FM women. Given the widely sited complaints of sleep disturbance in FM, sex hormones may significantly contribute to the link between sleep disturbance and other FM symptomatology in women.