MONDAY, Nov. 14 (HealthDay News) -- Sleep problems are associated with an increased risk of fibromyalgia in women, especially those who are middle-aged and older, a new study says.

Fibromyalgia is a chronic musculoskeletal pain condition that affects more than 5 million adults in the United States. Women account for up to 90 percent of people with fibromyalgia, which typically begins in middle age.

Previous research has found that insomnia, nighttime awakening and fatigue are common symptoms experienced by fibromyalgia patients, but it wasn't known if sleep problems contribute to the development of fibromyalgia.

Norwegian researchers enrolled 12,350 healthy women, 20 years and older, with no musculoskeletal pain or movement disorders and followed them for 10 years. At the end of that time, 327 (2.6 percent) of the women had developed fibromyalgia.

The study found a more than five-fold jump in the risk for fibromyalgia among women over 45 who often or always had sleep problems, and a nearly three-fold rise for women aged 20 to 44 with similar sleep woes.

The study appears online Nov. 14 in the journal Arthritis & Rheumatism.

"Our findings indicate a strong association between sleep disturbance and fibromyalgia risk in adult women," Dr. Paul Mork, from the Norwegian University of Science and Technology, said in a journal news release. "We found a dose-response relation, where women who often reported sleep problems had a greater risk of fibromyalgia than those who never experienced sleep problems."

While the study found an association between poor sleep and fibromyalgia, it did not demonstrate a cause and effect.

Further research is needed to determine whether early detection and treatment of sleep problems can reduce fibromyalgia risk in women, the researchers said.

More information

The U.S. National Institute of Arthritis and Musculoskeletal and Skin Diseases has more about fibromyalgia.