Sleep disorders associated with risk of rheumatoid arthritis

Immune disorders impair sleep quality and sleep disorders (SDs) may derange immune function.

The study evaluated the incidence and risk of rheumatoid arthritis (RA) in patients with SDs using a nationwide cohort.

We recognized the patients with SDs from 1998 to 2002 by using the Taiwan National Health Insurance Research Database. One control patient for each SD patient was randomly selected and matched based on the proportion of age, sex, and index year. We calculated the person years of follow-up for each participant from the index date to RA diagnosis, censoring, or until December 31, 2011. The risk of RA was estimated by using Cox models incorporating demographics and comorbidities.

We enrolled 65,754 patients with SDs and 65,753 controls and followed for 637,906 and 662,514 person-years, respectively. The patients with SDs exhibited a 1.49-fold greater risk of RA development compared with the comparison cohort when we adjusted for covariates. The patients with sleep apnea (SA) showed the greatest incidence density rate of RA, followed by those with non-apnea SDs and the non-SD cohort (4.11, 3.29, and 2.15 per 10,000 person-years, respectively). The SA cohort had a 2.56-fold adjusted hazard ratio (aHR) of RA (95% confidence interval [CI] = 1.11-5.91) and the non-apnea SD cohort had a 1.47-fold aHR of RA (95% CI = 1.18-1.84) compared with the non-SD cohort. Women with SDs presented a considerable risk of developing RA.

This nationwide cohort study indicates that SDs are associated with the risk of RA development.