Sleep Irregularity and the Incidence of Type 2 Diabetes: A Device-Based Prospective Study in Adults

Objective: To prospectively examine the association between device-measured sleep regularity and incidence of type 2 diabetes (T2D) in a population-based sample of adults. We also examined if meeting sleep duration recommendations attenuates or eliminates the effects of irregular sleep on T2D.

Research Design and Methods: Prospective cohort study of adults aged 40-79 years participating in the UK Biobank accelerometer substudy. Participants wore wrist-attached accelerometers for a duration of 7 days, which was used to compute the Sleep Regularity Index (SRI). Participants were categorized as irregular (SRI <71.6), moderately irregular (SRI between 71.6 and 87.3), and regular (SRI >87.3) sleepers. T2D diagnosis was obtained through self-reports and health records.

Results: We analyzed data from 73,630 individuals followed for 8 years, without a previous history of T2D and without an event in the first year of follow-up. Compared to regular sleepers, irregular (HR: 1.38, 95%CI: 1.20-1.59) and moderately irregular sleepers (HR: 1.35, 95%CI: 1.19-1.53) were at higher risk of T2D incidence. Dose-response analyses treating SRI as a continuous measure showed higher T2D incidence with SRI scores below 80. Meeting current sleep duration recommendations did not counteract the adverse effects of irregular (HR: 1.35, 95%CI: 1.09-1.66) or moderately irregular (HR: 1.29, 95%CI: 1.08-1.54) sleep on T2D incidence.

Conclusions: Moderate and high sleep irregularity were deleteriously associated with T2D risk, even among participants who slept ≥7 hours/night. Future sleep interventions will need to pay more attention to the consistency in bedtimes and wake-up times, in addition to sleep duration and quality.