Daily Variations in Objective Nighttime Sleep and Subjective Morning Pain in Older Adults with Insomnia: Evidence of Covariation over Time

OBJECTIVES To examine the relationship between objectively measured nocturnal sleep and subjective report of morning pain in older adults with insomnia; to examine not only the difference between persons in the association between sleep and pain (mean level over 14 days), but also the within-person, day-to-day association. DESIGN Cross-sectional. SETTING North-central Florida. PARTICIPANTS Fifty community-dwelling older adults (mean age +/- standard deviation 69.1 +/- 7.0, range 60-90) with insomnia. MEASUREMENTS Daily home-based assessment using nightly actigraphic measurement of sleep and daily self-report of pain over 14 consecutive days. RESULTS Between persons, average sleep over 14 days was not associated with average levels of rated pain, but after a night in which an older adult with insomnia experienced above-average total sleep time he or she subsequently reported below-average pain ratings. The model explained approximately 24% of the within-person and 8% of the between-person variance in pain ratings. CONCLUSIONS Sleep and pain show day-to-day associations (i.e., covary over time) in older adults with insomnia. Such associations may suggest that common physiological systems underlie the experience of insomnia and pain. Future research should examine the crossover effects of sleep treatment on pain and of pain treatment on sleep.