Arthritis, Sleep Health, and Systemic Inflammation in Older Men.

ObjectiveTo examine the associations of prevalent arthritis with systemic inflammation in older men and to test whether sleep health mediates the associations.MethodsCross-sectional data came from 2,562 community-dwelling older men (all were age 65 years or older; mean age 76 years) in the Osteoporotic Fractures in Men Study who participated in a sleep ancillary study in 2003-2005. Participants were classified as having osteoarthritis (OA) (24%) or rheumatoid arthritis (RA) (0.7%) based on self-reported diagnoses and medication use. We constructed a composite score of multidimensional sleep health (i.e., perceived sleep quality, sleepiness, frequency of daytime napping, wake after sleep onset, and sleep duration) measured by both self-report and actigraphy. We also created binary indicators of elevated inflammation using C-reactive protein (CRP) (>3 mg/liter) and interleukin-6 (IL-6) (>1.08 pg/ml) levels. Analyses controlled for age, diagnosed sleep disorders, body mass index, smoking status, relevant medication use, and comorbidities.ResultsOlder men with OA did not have higher risk of elevated CRP or IL-6 levels. However, indirect associations of OA through sleep health were found. OA was associated with poorer sleep health, which was further associated with 16% higher odds of elevated CRP (P < 0.001) and 12% higher odds of elevated IL-6 (P < 0.01) levels after controlling for OA. Older men with RA had higher odds of elevated CRP and IL-6 levels, but the associations were not mediated by sleep health.ConclusionFindings suggest that promoting sleep health may help reduce the risk of systemic inflammation in older men with OA