Sleep Duration Irregularity and Risk for Incident Cardiovascular Disease in the UK Biobank

Area of Science:

• Cardiology
• Sleep Science
• Public Health

Background:

• Circadian rhythm disruption, indicated by inconsistent sleep duration, is linked to increased cardiovascular disease (CVD) risk.
• The influence of CVD type, average sleep duration, and genetic predisposition on this association requires further investigation.

Purpose of the Study:

• To examine the association between sleep duration variability and the risk of major cardiovascular events.
• To determine if this association differs across CVD types (myocardial infarction, stroke) or is modified by average sleep duration and genetic risk.

Main Methods:

• Prospective analysis of 86,219 UK Biobank participants using 7-day accelerometer data.
• Sleep irregularity quantified by the standard deviation (SD) of sleep duration.
• Incident major CVD events (myocardial infarction, stroke) tracked via hospital records; Cox proportional hazard models used for analysis.

Main Results:

• A 1-hour increase in sleep duration SD was associated with a 19% increased risk of CVD (HR 1.19), 23% for myocardial infarction (HR 1.23), and 17% for stroke (HR 1.17).
• These associations remained significant after adjusting for various confounders.
• Sleep irregularity elevated CVD risk regardless of genetic risk but was more pronounced in individuals sleeping longer than 8 hours.

Conclusions:

• Higher night-to-night variation in sleep duration is consistently linked to increased major CVD event risk.
• Genetic risk for CVD did not modify this association.
• The heightened risk associated with sleep irregularity was more pronounced in long sleepers (average sleep >8 hours).