Sleep Disorders Modify the Age-Related Trajectory of Circadian Rest-Activity Rhythms: Evidence from NHANES 2011–2012 Wrist Actigraphy

Abstract Background Circadian rest-activity rhythms weaken with age, but whether sleep disorders modify this trajectory is unknown. Methods We analyzed wrist accelerometry data from 4,386 participants aged 6–80 years in the 2011– 2012 National Health and Nutrition Examination Survey (NHANES). Circadian features were extracted using cosinor analysis and nonparametric methods; a Circadian Disruption Index (CDI) was constructed from five standardized components. Survey-weighted regression with natural cubic splines and Wald F-tests tested age-by-sleep-disorder interactions using Taylor series linearization for variance estimation. Results Doctor-diagnosed sleep disorder ( N = 360, 8.2%) was associated with significantly different age-related trajectories of amplitude ( F (2, 17) = 11.24, p = 0.0008) and MESOR ( F (2, 17) = 8.22, p = 0.0032), both surviving Bonferroni correction ( p < 0.006). CDI was higher in those with a sleep disorder (0.290 vs. 0.131, p < 0.001) and was independently associated with higher BMI ( β = 1.33 kg/m 2 , p < 0.001), higher HbA1c ( β = 0.089%, p = 0.004), greater diabetes prevalence ( β = 3.8 percentage points, p < 0.001), and worse depressive symptoms ( β = 0.43 PHQ-9 points, p = 0.020). Sensitivity analyses using a broader sleep problem exposure did not replicate these interactions. Conclusions Doctor-diagnosed sleep disorders are associated with an altered age-related decline in circadian amplitude and mean activity level. CDI was independently linked to cardiometabolic and depressive outcomes, supporting a mechanistic connection between clinically significant sleep pathology and circadian disruption across the lifespan.