Chronotype, Life's Essential 8, and risk of cardiovascular disease: a prospective cohort study in UK Biobank

Area of Science:

• Cardiology
• Chronobiology
• Public Health

Background:

• Circadian misalignment in evening chronotypes may negatively impact health behaviors and cardiometabolic functions.
• The relationship between chronotype, modifiable cardiovascular disease (CVD) risk factors, and incident CVD requires further clarification.

Purpose of the Study:

• To investigate the association between chronotype and cardiovascular health.
• To determine the role of modifiable CVD risk factors in the link between chronotype and incident CVD.

Main Methods:

• Prospective analysis of 322,777 UK Biobank participants (aged 39-74) without prior CVD.
• Chronotype assessed via self-reported questionnaire; cardiovascular health evaluated using the Life's Essential 8 (LE8) score.
• Incident CVD (myocardial infarction or stroke) identified through validated algorithms; Cox proportional hazards models and causal mediation analysis employed.

Main Results:

• Individuals with definite evening chronotype (8% of sample) were 79% more likely to have poor LE8 scores compared to intermediate chronotype.
• Over 13.2 years, definite evening chronotype was associated with a 16% higher hazard ratio for total CVD (HR: 1.16; 95% CI: 1.10-1.22) versus intermediate.
• The Life's Essential 8 score mediated 74% of the association between evening chronotype and CVD risk.

Conclusions:

• Evening chronotype is associated with a modestly increased risk of cardiovascular disease (CVD).
• Poorer cardiovascular health, as measured by the LE8 score, largely explains the elevated CVD risk in evening chronotype individuals.
• Targeted interventions for cardiovascular risk factors may be particularly beneficial for those with an evening chronotype.