A new study suggests that sleep may be an important mediator for systemic inflammation and osteoarthritis (OA) in older adults and shows that better sleep can decrease pain level. The research recently published in the journal for Arthritis Care & Research analyzed data from the Osteoporotic Fractures in Men Study, which included a cross-sectional sample of 2562 men over 65 years old with either OA or rheumatoid arthritis (RA). Soomi Lee, PhD, assistant professor in the School of Aging Studies, examined whether systemic inflammation often found in patients with OA or RA is explained by poorer sleep health.
“OA and RA are each characterized by joint destruction. In both diseases, inflammation is implicated. However, OA by itself is not a systemic inflammatory disease and it typically involves the greatest pain at the end of the day, whereas RA usually involves the greatest pain in the morning. Given these differences, we were curious whether and how sleep health contributes to the mechanisms of OA and RA leading to systemic inflammation.” Lee said.
The study contributes to an emerging method of analyzing how sleep health is determined by multiple aspects, such as perceived sleep quality, sleepiness, napping, disturbances, and duration. Lee’s research work examines how sleep, stress and chronic diseases affect older populations by applying various testing methods, which range from daily diaries to electronic devices to biomarkers. Cross-sectional population samples are used to best assess which factors are contributing to sleep health and affect overall health in old age.
Participants self-reported their sleep quality and also wore sleep monitoring devices for a period of five consecutive days. Lee’s research team then used assays to test blood samples to measure biomarkers of systemic inflammation – C-reative protein (CRP) and interleukin-6 (IL-6). They found that having OA was associated with experiencing poor sleep health, and poor sleep health was further associated with having higher risk of elevated CRP and IL-6. RA was directly associated with having a higher risk of elevated CRP and IL-6. This association was not mediated by poor sleep health after accounting for a wide array of relevant medications and co-morbidities.
Results from this study reveal different potential mechanisms by which OA and RA may increase risk for systemic inflammation and suggests that promoting sleep health in men with OA may help reduce the risk of systemic inflammation. Further scientific efforts are needed to identify pain stressors with the goal of decreasing them in older adults who suffer from joint destruction and to recommend health care professionals to promote sleep health.
The study was co-authored by Dr. Lee’s colleagues at Penn State, Drs. Orfeu M. Buxton and Christopher G. Engeland, and at the University of California, Drs. Katie Stone and Nancy E. Lane.