Both insufficient and prolonged sleep durations on weekdays are significantly associated with rheumatoid arthritis, with a U-shaped relationship identified, particularly in individuals aged 40 to 79 and those with obesity.
Key Findings
Results
A U-shaped relationship between weekday sleep duration and rheumatoid arthritis was identified, with significant increases in odds of RA for sleep durations both below and above 7 hours.
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 adjusted models 2 and 3 (p < 0.001 and p = 0.0055, respectively)
Significant increase in odds of RA was observed for sleep durations both below and above 7 hours (P < 0.05)
The study included 9,385 participants aged 20 years and older from NHANES
Results
A linear trend between weekday sleep duration and RA presence was observed in less-adjusted models but disappeared after full covariate adjustment.
Linear trend was significant in both logistic regression models 1 and 2 (p < 0.0001 and p = 0.01, respectively)
The linear relationship was no longer evident in the fully adjusted model 3 (p = 0.96)
This suggests that confounding variables accounted for in model 3 explain the apparent linear association
Methods
The study sample comprised 2,595 participants with RA and 6,790 non-RA participants drawn from NHANES.
Total cohort consisted of 9,385 participants aged 20 years and older
RA status was determined via self-reported questionnaires
Sleep duration on weekdays data were collected through personal interviews
This was a cross-sectional study design
Results
Subgroup analysis indicated a significant interaction between age stratification (40–79 years old) and the association between sleep duration and RA.
P for interaction < 0.05 for the age group of 40–79 years old
The association between sleep duration and RA was particularly notable in this age subgroup
Individuals with obesity also showed a significant interaction with the sleep duration–RA association
Conclusions
Both insufficient and prolonged weekday sleep durations are significantly associated with rheumatoid arthritis, especially in individuals aged 40 to 79 and those with obesity.
The U-shaped relationship suggests 7 hours of sleep as the inflection point associated with lowest RA odds
The association was particularly pronounced in the 40–79 year age group and in obese individuals
Multivariable logistic regression and restricted cubic spline regression were used to estimate the association
Results held after adjustment for multiple covariates in model 3 for the nonlinear (U-shaped) component (p = 0.0055)
What This Means
This research suggests that how long people sleep on weekdays is linked to whether they have rheumatoid arthritis (RA), a chronic inflammatory joint disease. Using data from nearly 9,400 American adults in a large national health survey, researchers found a U-shaped pattern: people who slept either too little or too much had higher odds of having RA compared to those who slept around 7 hours per night. This U-shaped relationship held up even after accounting for many other health and lifestyle factors.
The association was especially strong among adults between the ages of 40 and 79 and among people with obesity. In simpler statistical models, there appeared to be a straightforward linear relationship (more sleep linked to less RA), but this disappeared once researchers fully adjusted for other variables, leaving only the U-shaped nonlinear pattern. This suggests that the relationship between sleep and RA is more complex than a simple 'more sleep is better' conclusion.
This research suggests that both short and long sleep durations may be markers of or contributors to rheumatoid arthritis risk, particularly in middle-aged to older adults and those carrying excess weight. Because this was a cross-sectional study — meaning it captured a snapshot in time rather than following people over years — it cannot establish whether poor sleep causes RA or whether RA disrupts sleep. Still, the findings highlight sleep duration as a potentially important factor to consider in understanding RA risk patterns in the general population.
Ye D, You X, Lin C, Wu Y, Xu C, Ye S. (2026). The association of sleep duration on weekdays with rheumatoid arthritis: a cross-sectional study from NHANES.. BMC public health. https://doi.org/10.1186/s12889-026-26679-9