Background The patients with rheumatoid arthritis (RA) may exhibit a considerable experience of poor sleep quality, which is due to RA related joint pain. Meanwhile, sleep disturbance may exacerbate fatigue, depression and pain in RA. Sleep exerts a strong regulation of immune function. Studies on the relationship between sleep disorders and the subsequent risk of RA are scarce.
Objectives The aim of the study is to determine whether the patients with sleep disorders increase the risk of RA development by using a nationwide cohort study in an Asian population.
Methods Using the Taiwan National Health Insurance Research Database (NHIRD), we identified patients with sleep disorders (including sleep apnea and non-apnea sleep disorders) from 1998 to 2010. All insured people without a history of sleep disorders and RA in the NHIRD became a potential comparison cohort. One control participant for each case with sleep disorders were randomly selected frequency matched for age, sex, and index year. The follow-up person-years were estimated for study participants from the index date to RA diagnosis, censoring caused by death, loss to follow-up, withdrawal from the insurance system, or until the end of December 31, 2011. The risk of RA was analyzed using Cox proportional hazards regression models including demographic characteristics and comorbidities.
Results A total of 65 754 patients with sleep disorders (including 1404 sleep apnea disorders and 64350 nonapnea sleep disorders) and 65 753 controls were included in the current study. Most of the study participants were women (62.8%). The mean ages were 51.3 (±16.1) years in patients with sleep disorders and 51.1 (±16.3) years in comparison cohort. The incidence density rate was the highest in the patients with apnea sleep disorders, followed in the patients with non-apnea sleep disorders and the comparison cohort (4.11, 3.29, and 2.15 per 10 000 person-y, respectively). Compared to the comparison cohort, the adjusted hazard ration (HR) of RA was 2.62 (95% CI =1.14-6.04) in the cohort with apnea sleep disorders and 1.47 (95% CI =1.18-1.84) in the cohort with non-apnea sleep disorders after adjusting for covariates. Women with sleep disorders exhibited a considerably higher risk of RA than did women without sleep disorders.
Conclusions This nationwide cohort study demonstrated that the sleep disorders may become an independent risk factor for RA. Future study to confirm the observational epiphenomenon is warranted.
Abad VC, Sarinas PS, Guilleminault C. Sleep and rheumatologic disorders. Sleep Med Rev 2008;12:211-28.
Loppenthin K, Esbensen BA, Jennum P, et al. Sleep quality and correlates of poor sleep in patients with rheumatoid arthritis. Clin Rheumatol 2015.
Irwin MR, Olmstead R, Carrillo C, et al. Sleep loss exacerbates fatigue, depression, and pain in rheumatoid arthritis. Sleep 2012;35:537-43.
Diekelmann S, Born J. The memory function of sleep. Nat Rev Neurosci 2010;11:114-26.
Schmidt EM, Linz B, Diekelmann S, Besedovsky L, Lange T, Born J. Effects of an interleukin-1 receptor antagonist on human sleep, sleep-associated memory consolidation, and blood monocytes. Brain Behav Immun 2014.
Acknowledgements This work got partial grant support from the Taichung Hospital, Ministry of Health and Welfare and administrative support from China Medical University.
Disclosure of Interest None declared