Preliminary investigation of interactive associations of sleep and pain with cognition in sedentary middle-aged and older adults.

Study Objectives: The objective of this study was to examine independent and interactive associations between self-reported sleep (sleep efficiency and total sleep time [TST]) and pain with cognition in sedentary middle-aged and older adults.

Methods: Seventy-five sedentary adults at least 50 years of age (M = 63.24, standard deviation = 8.87) completed 14 daily diaries measuring sleep and pain. Weekly average sleep efficiency, TST, and pain were computed. Participants also completed computerized cognitive tasks: Letter Series (reasoning), N-back (working memory), Symbol Digit Modalities Test (processing speed, attention), and Number Copy (processing speed). Multiple regression analyses were conducted to determine independent and interactive (with pain) associations of sleep efficiency and TST with cognition, controlling for age, education, and sex.

Results: Sleep efficiency and pain interacted in their associations with Letter Series performance and N-back difference scores (2-back minus 1-back). Specifically, higher sleep efficiency was associated with better reasoning and working memory in those with highest pain but not average or lowest pain. TST and pain also interacted in their associations with Letter Series performance. Specifically, longer TST associated with worse reasoning in those with lowest (not average or highest) pain.

Conclusions: Preliminary results show that in sedentary middle-aged and older adults, pain and sleep interact in their associations with executive function tasks. Higher sleep efficiency may be associated with better reasoning and working memory in those with highest pain. Lower TST may be associated with better reasoning in those with lowest pain. Studies evaluating temporal associations between sleep, pain, and cognition are needed.