Knee Pain Worse with Insomnia
Could getting better sleep ease the knee pain that comes from osteoarthritis? New research at Johns Hopkins University Hospital suggests that's the case, finding that the combination of arthritis and insomnia can increase a person's sensitivity to pain.
The researchers compared pain in four groups: one group with insomnia and knee osteoarthritis, one group without insomnia but suffering from knee osteoarthritis, one group of healthy people with insomnia, and one group of healthy people with no trouble sleeping. The group of healthy people had no history of chronic pain over the past three years with no major medical or psychiatric illnesses as well. They were asked to keep sleep diaries, participated in one-night sleep studies in a lab to test the quality of rest, and took pain threshold tests using heat and cold.
Osteoarthritis is a degenerative disease that erodes cartilage, the slippery tissue that covers the ends of bones in a joint, causing pain, swelling, loss of motion and bone spurs. It is associated with aging. It typically strikes the most used joints, including the knees, hips, fingers and lower spine. Globally, about one in 10 men and one in five women over age 60 have osteoarthritis.
According to the results of the Johns Hopkins study, published in Arthritis Care and Research, people with knee osteoarthritis and insomnia were most sensitive to pain, as well as having the most interruptions in their sleep.
While the study shows that insomnia may have a big effect on how people with osteoarthritis perceive pain, it doesn't prove that insomnia causes pain.