At the study’s outset, roughly two-thirds of the women said they had no difficulty sleeping. Compared with that group, those who said they “sometimes” had trouble falling asleep or had any sleep disorder during the previous month had double the risk of developing fibromyalgia. The risk was three and a half times greater among those who said they “often or always” had sleep problems.
The link appeared to be especially strong among women age 45 and older. Women in that age group who reported often or always having sleep problems had a more than fivefold increased risk of fibromyalgia compared to sound sleepers, while the corresponding risk among younger women was just three times greater.
The study has some key shortcomings. The researchers relied on the women’s own assessment of their sleep problems and fibromyalgia symptoms, as opposed to official diagnoses. And though they took several potentially mitigating factors (such as body mass index, depression, and education levels) into account, they lacked data on anxiety, which has been linked to both sleep problems and fibromyalgia.
Other important factors that weren’t measured in the study include menopausal status and a history of physical or psychological trauma, says Carol A. Landis, a professor at the University of Washington School of Nursing, in Seattle. As many as 30% to 50% of women with fibromyalgia report a history of trauma, Landis says.
Still, “The weight of the evidence really supports the important role of sleep in fibromyalgia,” Arnold says. “We don’t always understand what the biological mechanisms are underlying that association between sleep and pain, but clearly there’s an important connection.”
Doctors and patients should be aware of this connection and should address sleep problems—especially unrefreshing sleep—to lower the risk of the patient developing chronic pain, Arnold says.
“Sleep problems should be taken seriously,” Mork says. “In addition to being a risk factor for fibromyalgia, sleep problems are also associated with increased risk of other chronic diseases,” such as heart disease, he adds. “Early detection and proper treatment may therefore reduce the risk of future chronic disease.”