New research from the UK finds that among adults over the age of 50, non-restorative sleep - the sort where you wake up feeling tired and worn out - is strongly tied to onset of widespread pain, a hallmark of fibromyalgia.

They also found that anxiety, memory impairment and poor physical health were linked to higher risk of developing widespread pain in older adults.

Dr. John McBeth, of the Arthritis Research UK Primary Care Centre at Keele University in Staffordshire, and colleagues report their findings in the journal Arthritis & Rheumatology.

Musculoskeletal pain (affecting muscle, bone and nerve) becomes more common with age, to the point where from age 65 onward, 4 out of 5 people have pain every day.

Widespread pain is a key feature of fibromyalgia, a condition where the sufferer typically experiences fatigue accompanied by long-term pain in several areas of the body, plus tenderness in the muscles, joints, tendons and other soft tissues.

Estimates suggest around 5 million Americans aged 18 and over are affected by fibromyalgia, and for reasons unknown, the vast majority of those diagnosed with the condition are women, although it can also affect men and children. Most people are diagnosed in middle age, although symptoms are often present earlier.

Study identified several factors linked to development of widespread pain

For their study, Dr. McBeth and colleagues identified factors linked to increased risk of developing widespread pain in older adults.

The data they studied came from over 4,300 adults over the age of 50 who were free of widespread pain at the start of the study period, including around 2,700 who reported having some - but not widespread - pain.

At the start of the study, the participants filled in questionnaires about pain, mental and physical health, lifestyle and health behaviors, medical conditions and sociodemographic status.

They were followed for 3 years and re-assessed for development of widespread pain (using American College of Rheumatology Criteria). The researchers then analyzed the data using statistical tools to find which factors were most strongly linked with onset of widespread pain.

The results showed that at the 3-year follow-up, 19% of the participants reported new widespread pain. This included 25% of participants who had reported some pain and 8% who had reported no pain at the start of the study.

More evidence of a link between poor sleep and widespread pain

The researchers found that pain status (some pain or no pain), anxiety, physical health-related quality of life, having some form of cognitive complaint and non-restorative sleep were linked to increased risk of developing widespread pain.

But the strongest link to development of widespread pain was with non-restorative sleep.

However, the study was not designed to establish cause and effect, so the researchers cannot say whether non-restorative sleep is a cause or effect of fibromyalgia.

Prof. Alan Silman, medical director of Arthritis Research UK says the study is important because it provides more evidence of a link between poor sleep and widespread pain or fibromyalgia.

"Brainwave studies have shown that people with this condition often lose deep sleep," he explains, adding that "in an experiment where healthy volunteers were woken during each period of deep sleep, a number of them developed the typical signs and symptoms of fibromyalgia."

He says pain, sleep disturbance and anxiety can combine to form a vicious cycle but adds that "research has also shown that aerobic exercise improves fitness and reduces pain and fatigue, and should also improve sleep and wellbeing."

In 2011, Medical News Today reported another study from Norway where researchers found women who experienced poor sleep had an increased risk of fibromyalgia.