Circadian preference and risk of myocardial infarction: Findings from a longitudinal community-based study.

OBJECTIVES

Myocardial infarction remains a major cause of morbidity and mortality worldwide. Beyond traditional risk factors, circadian preference has emerged as a potential determinant of cardiovascular health, yet its role in myocardial infarction risk remains underexplored.

METHODS

We analyzed 4578 adults aged ≥40 years from the Sleep Heart Health Study. Chronotype was derived using the standard Munich Chronotype Questionnaire (MCTQ) algorithm applied to self-reported bedtimes and wake times, and categorized as morning, intermediate, or evening type. Incident myocardial infarction events were adjudicated during a mean follow-up of 10.6 years. Cox proportional hazards models estimated hazard ratios (HRs) adjusting for demographic, lifestyle, cardiometabolic, and polysomnography-derived sleep parameters, with stratified analyses by obstructive sleep apnea.

RESULTS

Compared with intermediate chronotypes, both morning (HR = 1.50, 95% CI 1.10-2.05) and evening types (HR = 1.40, 95% CI 1.00-1.95) exhibited significantly higher myocardial infarction risk after full adjustment. These associations were substantially stronger among participants with obstructive sleep apnea (morning HR = 1.85; evening HR = 1.82), whereas no significant association was observed in those without obstructive sleep apnea. Notably, the "morning" group did not confer the lowest risk.

CONCLUSIONS

Chronotype was independently associated with long-term myocardial infarction risk, with intermediate chronotype showing the lowest risk. These findings suggest that extreme chronotypes may be less favorable for cardiovascular health, particularly in individuals with obstructive sleep apnea. Incorporating chronotype into risk stratification may improve myocardial infarction prevention strategies.

CLINICAL TRIAL REGISTRATION: This study is a secondary analysis of the Sleep Heart Health Study (ClinicalTrials.gov Identifier: NCT00005275).