Mild circadian rhythm disruption resulting from irregular sleep timing and duration patterns may be associated with an increased risk for cardiovascular disease (CVD) events, according to a study published in the Journal of the American College of Cardiology.

A total of 1992 participants free of CVD who were enrolled between 2010 and 2013 in the Multi-Ethnic Study of Atherosclerosis were asked to complete a 7-day wrist actigraphy to assess sleep patterns. Participants were followed through 2016. Sleep regularity was evaluated by measuring the standard deviations (SDs) of sleep duration and sleep-onset timing over a 7-day period assessed using actigraphy. These SDs were adjusted for average sleep duration and known risk factors for CVDs. Participants also completed a sleep questionnaire to assess their sleep habits and traits.

In this cohort, 111 participants developed CVD events (ie, fatal or nonfatal cardiovascular events) during a median follow-up period of 4.9 years. The overall incidence rate of CVD events was 11.8 per 1000 person-years.

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Hazard ratios (HRs) for CVD events for different patterns of circadian rhythm disruptions were compared with the reference, sleep duration with an SD ≤60 minutes (HR, 1.00). HRs for CVD events were 1.07 (95% CI, 0.61-1.88) for sleep duration with an SD between 61 and 90 minutes, 1.54 (95% CI, 0.89-2.65) for sleep duration with an SD between 91 and 120 minutes, and 2.02 (95% CI, 1.20-3.39) for sleep duration with an SD >120 minutes.

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For every 1-hour increase in sleep duration SD, there was an associated 36% increased risk for CVD (95% CI, 1.07-1.73; P =.02). There was an 18% increased risk for CVD for every 1-hour increase in sleep-onset timing SD (95% CI, 1.06-1.31; P =.002).

Limitations of the study include a modest sample size, a relatively short follow-up period, and the inability to exclude residual and unmeasured confounding factors.

 “[O]ur results support considering inconsistent sleep patterns as a novel CVD risk factor and suggest the need to evaluate the role of healthy sleep practice interventions as a strategy for cardiovascular risk reduction,” concluded the study authors.

Disclosure: Several study authors declared affiliations with the pharmaceutical industry. Please see the original reference for a full list of authors’ disclosures.


Huang T, Mariani S, Redline S. Sleep irregularity and risk of cardiovascular events: the multi-ethnic study of atherosclerosis. J Am Coll Cardiol. 2020;75(9): 991-999.