Sleep and Cardiometabolic Disease: A Wearable-Electronic Health Record Study in the US All of Us Research Program

Background: Sleep health spans duration, quality, regularity, and timing, yet Life's Essential 8 scores sleep by duration alone, and regularity studies used about 1 week of data. How these dimensions, measured over months, relate to incident cardiometabolic disease is unknown, as is whether nightly sleep-cycle structure adds information. Methods: This cohort study included US adults in the All of Us Research Program with linked Fitbit and electronic health records (2009–2023). We derived 11 sleep metrics over a 180-day baseline (≥90 valid nights). Incident diagnoses, grouped into phecodes, were counted after a 180-day washout to limit reverse causation. Primary analyses related these metrics to prespecified endpoints, including a CVD composite (myocardial infarction, heart failure, cardiomyopathy, or ischemic stroke), heart failure, hypertension, and type 2 diabetes. Cox models adjusted for demographic, socioeconomic, lifestyle, and comorbidity factors. Exploratory analyses examined wearable-estimated sleep cycles (7,199 participants; 1,017,812 sleep-stage nights). Results: Among 10,362 participants (median age, 53 years; 70% female), 230 developed the CVD composite (median follow-up, 3.7 years). Each 1-SD (29-minute) higher night-to-night variability in sleep duration was associated with higher CVD composite risk (hazard ratio, 1.24 [95% CI, 1.09–1.41]), as was higher variability in bedtime (1.23 [1.10–1.37]), waketime (1.20 [1.09–1.32]), and midpoint (1.21 [1.09–1.35]); mean sleep duration was not (0.96 [0.85–1.08]). Variability in sleep duration was also associated with heart failure (1.32 [1.13–1.55]), hypertension (1.16 [1.08–1.25]), and type 2 diabetes (1.20 [1.07–1.35]). More sleep cycles were associated with lower atrial arrhythmia risk (0.72 [0.58–0.89]), independent of sleep duration, regularity, and timing (0.58 [0.44–0.77]). Conclusions: Night-to-night irregularity in sleep duration and timing was associated with the CVD composite, heart failure, hypertension, and type 2 diabetes; mean duration was not associated with the CVD composite. More wearable-estimated sleep cycles were associated with lower atrial arrhythmia risk beyond conventional sleep metrics, a novel finding requiring confirmation.