Pain as a mediator of sleep problems in arthritis and other chronic conditions.
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.


CONCLUSIONS
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.
Power
J Denise
JD
University of Toronto, and Toronto Western Research Institute, University Health Network, Toronto, Ontario, Canada. dpower@uhnres.utoronto.ca
Perruccio
Anthony V
AV
Badley
Elizabeth M
EM
D000293:Adolescent; D000328:Adult; D000368:Aged; D001168:Arthritis / Q000453:epidemiology* / Q000503:physiopathology; D002170:Canada / Q000453:epidemiology; D015897:Comorbidity; D003430:Cross-Sectional Studies; D020920:Dyssomnias / Q000175:diagnosis / Q000453:epidemiology*; D005260:Female; D006801:Humans; D008019:Life Style; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D010146:Pain / Q000453:epidemiology*; D007319:Sleep Initiation and Maintenance Disorders / Q000175:diagnosis / Q000453:epidemiology*