Objective: To examine the associations between arthritis and insomnia symptoms and unrefreshing sleep, as well as the role of pain as a mediator of these relationships.
Methods: Analyses were conducted on the cross-sectional, nationally representative, weighted sample of adults > or =18 years of age (n = 118,336) in the 2000/2001 Canadian Community Health Survey. Four logistic regression models were estimated for each sleep problem (model 1: arthritis only; model 2: model 1 + sociodemographic characteristics, lifestyle factors, and other chronic conditions; model 3: model 2 + mental health [stress, depression]; and model 4: model 3 + pain). Mediation by pain was quantified by the percentage change in the effect of arthritis on a particular sleep problem by comparing models 3 and 4.
Results: The prevalence of insomnia symptoms and unrefreshing sleep in persons with arthritis was 24.8% and 11.9%, respectively. These estimates are twice as high as those for persons without arthritis. In multivariate regression analyses, the addition of pain decreased the effect of arthritis by 53% (insomnia symptoms) and 64% (unrefreshing sleep). The effect of arthritis was still statistically significant in these models, suggesting that pain is a partial mediator of these relationships.
Conclusion: Insomnia symptoms and unrefreshing sleep affect a considerable proportion of individuals with arthritis. Pain mediates a substantial amount of the relationship between arthritis and sleep problems. Better pain management could significantly improve sleep in individuals with arthritis.