Daylight Saving Time and Acute Myocardial Infarction: A Meta-Analysis.
Level 3 - non-randomized controlled study
Systematic review and meta-analysis of observational (cohort and case-control) studies
PubMed 30909587 · doi:10.3390/jcm8030404
What was done
Authors conducted a systematic review and meta-analysis of cohort and case-control studies in MedLine and Scopus (up to December 31, 2018) assessing acute myocardial infarction (AMI) incidence in adults (≥18 years) following spring and/or autumn daylight saving time (DST) transitions compared to control periods. Summary odds ratios (ORs) were calculated using generic inverse-variance weighting for overall transitions and each transition separately, with subgroup analyses by age and sex.
What was found
Seven studies covering >115,000 subjects were included. AMI risk increased significantly over the two weeks following spring or autumn transitions combined (OR: 1.03; 95% CI: 1.01–1.06). Stratified by season, AMI risk was significantly higher in the week following the spring transition (OR: 1.05; 95% CI: 1.02–1.07), but was not significantly increased after the autumn transition (OR: 1.01; 95% CI: 0.98–1.04). Age and sex stratifications showed no substantial differences.
Why it matters
This review aggregates existing observational data to quantify the cardiovascular disruption associated with clock changes, demonstrating that the small observed increase in AMI risk is confined largely to the spring transition.
Limits
The analysis relies on a small total number of studies (7), all of which are observational and vulnerable to residual confounding. The effect sizes are very small (OR 1.03–1.05), where minor unadjusted biases could account for the observed associations.
Cited by
- contradicts In the three days following the spring transition into daylight saving time, heart attacks increase by an average of 24% across 70 countries.
- contradicts When falling back for daylight saving time and gaining one hour of sleep, heart attacks decrease by 21% across countries that observe it.