The association of sleep duration on weekdays with rheumatoid arthritis: a cross-sectional study from NHANES

Slumber constitutes an indispensable facet of our daily existence, with the duration of rest for each individual comprising approximately one-third of their entire lifespan. The objective of this study was to elucidate the relationship between sleep duration on weekdays and rheumatoid arthritis (RA) within the United States (US) population.

In this cross-sectional study, a cohort of 9,385 participants, aged 20 years and older, was meticulously selected from the National Health and Nutrition Examination Survey (NHANES). Sleep duration on weekdays data were collected through personal interviews, while RA status was determined via self-reported questionnaires. Sleep duration on weekdays was the main exposure variable, and RA was the outcome variable. The association between sleep duration on weekdays and RA was estimated by using the multivariable logistic regression models and restricted cubic spline (RCS) regression.

A total of 2,595 participants with RA and 6,790 non-RA participants were included in the study. A linear trend between sleep duration on weekdays and the presence of RA (p < 0.0001, p = 0.01, respectively) was observed in both logistic regression models 1 and 2. However, this linear relationship was no longer evident in model 3 (p = 0.96). The results of RCS analysis in Model 1 identified a U-shaped relationship between sleep duration on weekdays and the presence of RA (p < 0.001). This U-shaped relationship persisted in the adjusted models 2 and 3 (p < 0.001, p = 0.0055, respectively). They revealed a significant increase in the odds of RA for sleep durations both below and above 7 h (P < 0.05). Subgroup analysis indicated a significant interaction between age stratification (40-79 years old) and the association between obesity and RA (P for interaction < 0.05).

Our research indicates that both insufficient and prolonged sleep durations are significantly associated with RA, particularly in individuals aged 40 to 79 and those with obesity.