When Sleep Hurts the Joints: Longitudinal Associations of Sleep Quality and Duration with Incident Arthritis in the English Longitudinal Study of Aging

To examine the associations of sleep quality, sleep duration, and their trajectories with the risk of incident arthritis in middle-aged and older adults in the United Kingdom. Data from waves 4 to 8 of the English Longitudinal Study of Aging were used. We included 3028 participants aged ≥50 years without arthritis at baseline, followed for ∼8 years. Sleep quality was assessed using the Jenkins Sleep Scale (JSS), categorized as good, intermediate, or poor. Sleep duration was divided into tertiles. Incident arthritis was self-reported and physician-diagnosed. Associations were estimated using multivariable logistic regression and stratified analyses, including restricted cubic spline (RCS) models to explore dose–response relationships. Overall, 559 cases of incident arthritis were identified. Both intermediate and good sleep quality were associated with a lower risk of arthritis compared to poor sleep (odds ratio [OR] intermediate = 0.71, OR good = 0.55, P for trend < 0.001). The longest sleep tertile (Q3) showed a modest protective effect (OR = 0.72). RCS analysis revealed a significant linear dose–response relationship between JSS scores and arthritis risk. Sensitivity analyses of sleep-quality trajectories showed lower arthritis risk in all but the stable poor pattern, with the lowest risk in the stable good group (OR = 0.44). Poor subjective sleep quality is a more consistent predictor of arthritis than short-sleep duration alone, with a clear dose–response gradient. Improving poor sleep quality may be key to reducing arthritis risk.