Pain inconsistency and sleep in mid to late-life: the role of depression.

Objectives: Inconsistency in pain may lead to depression, which may then influence sleep. Thus, the purpose of this study was to examine whether depression mediates the relationship between day-to-day inconsistency in pain and sleep in middle aged to older adults. Methods: Baseline measures from the Active Adult Mentoring Project were used for secondary data analysis. Participants included 82 adults in mid- to late-life. Pain was assessed for seven consecutive days on an 11-point Likert-scale, with pain inconsistency defined as the seven-day individual standard deviation. A self-report daily diary was used to assess sleep efficiency (SE), total wake time (TWT), total sleep time (TST), and sleep quality (SQ), and depression was assessed using the BDI-II. Results: Mediation analyses revealed that depression partially mediated the relationship between pain inconsistency and SE, TWT, and SQ but not TST. Conclusions: Results indicate that depression may be an important factor through which pain inconsistency influences sleep. Although further research is warranted, these preliminary findings suggest that intervening on both pain inconsistency and depression may be one way to improve sleep in older adults.