Washington, Oct 6 (IANS): New research has confirmed that sleep disturbances are initially associated with depressive symptoms and pain but not disability. Over time, however, poor sleep was found to increase depressive symptoms and disability but not pain.

"Sleep disturbance is a common complaint among those with pain, particularly among those with osteo-arthritis (OA)," said Patricia Parmelee from the University of Alabama in the US.

The study examined the dynamics between sleep, pain, disability and depressive symptoms in patients with OA, finding complex associations between them as part of a cycle of distress.

"Our research is unique as we investigate the complex relationships among sleep, OA-related pain, disability and depressed mood simultaneously in a single study," Parmelee added.

For the study, 288 patients with knee OA provided information on sleep disturbances, pain, functional limitations and depressive symptoms for baseline analyses.

Longitudinal analyses took the baseline sleep disturbance readings and used them to prdict changes in pain, depression and disability over a one year period.

Participants who reported high levels of pain had symptoms of depression exacerbated through a combination of poor sleep and pain.

The study appeared in the journal Arthritis Care and Research.