Objective
It is known that osteoarthritis (OA) increases risk of sleep
disturbance, and that both pain and sleep problems may trigger functional
disability and depression. However, studies examining all four variables
simultaneously are rare. This research therefore examined cross-sectional
and longitudinal associations of self-reported sleep disturbance with
OA-related pain and disability, and depressive symptoms.
Methods
At baseline, 367 persons with physician-diagnosed knee OA reported
sleep disturbances, pain, functional limitations, and depressive symptoms.
All measures were repeated a year later (N = 288). Baseline analyses
examined the independent and interactive associations of sleep disturbance
with pain, disability and depression, net of demographics and general
health. Longitudinal analyses used baseline sleep disturbance to predict
one-year change in pain, disability and depression.
Results
At baseline, sleep was independently associated with pain and
depression, but not disability. The sleep-pain relationship was mediated by
depressive symptoms; sleep interacted with pain to exacerbate depression
among persons with high levels of pain. Baseline sleep disturbance predicted
increased depression and disability, but not pain, at follow-up.
Conclusions
These data confirm known cross-sectional relationships of sleep
disturbance with pain and depression, and provide new insights on
longitudinal associations among those variables. Depression appears to play
a strong role in the sleep-pain linkage, particularly where pain is severe.
The unique predictive role of sleep in progression of disability requires
further study, but may be an important point of intervention to prevent
OA-related functional decline among persons whose sleep is disrupted by OA
pain.