Sleep pattern, genetic risk, and the risk of incident rheumatoid arthritis: A cohort study.

Objective: To investigate the associations of sleep behaviors with the risk of rheumatoid arthritis, and whether the associations differ among individuals with low, intermediate, or high genetic risk.

Methods: We included participants who were free of rheumatoid arthritis at baseline based the UK Biobank. We evaluated the associations of five sleep behaviors with the risk of rheumatoid arthritis using Cox proportional hazard regression models. We then generated a sleep risk score which combined five sleep behaviors and assessed its association with the risk of rheumatoid arthritis. We finally generated a genetic risk score and examined the joint effects of sleep patterns and genetic susceptibility on the risk of rheumatoid arthritis.

Results: Of the 375,133 participants at baseline, 4913 incident rheumatoid arthritis cases were identified over a median follow-up of 11.73years. We found that insomnia and daytime sleepiness were associated with a 33% and a 38% increased risk of rheumatoid arthritis. A U-shaped association was observed between sleep duration and the risk of rheumatoid arthritis, with a 29% higher risk for those with short sleep and a 30% higher risk for those with long sleep. Participants with unfavorable sleep patterns had a 63% increased risk of rheumatoid arthritis compared with those with favorable sleep patterns. Participants with unfavorable sleep patterns and high genetic risk showed the highest risk of rheumatoid arthritis although no statistically significant multiplicative or additive interaction was found.

Conclusions: Our study suggested that insomnia, daytime sleepiness, and short or long sleep duration, as well as sleep risk score were associated with an increased risk of rheumatoid arthritis.