Daylight Saving Time Transitions and Risk of Heart Attack.
Level 3 - non-randomized controlled study
Systematic review and meta-analysis of observational studies
PubMed 38888468 · doi:10.3238/arztebl.m2024.0078
What was done
Authors conducted a systematic review and meta-analysis across eight databases through September 2023 examining acute myocardial infarction (AMI) rates in the first few weeks following daylight saving time (DST) transitions. Study quality was evaluated using the Newcastle-Ottawa Scale, and meta-regressions and sensitivity analyses were performed.
What was found
Twelve studies from ten countries were included (9 adequate quality, 3 good quality). The pooled relative risk (RR) for AMI following the spring transition was 1.04 (95% CI [1.02, 1.07], I² = 57.3%), and after the autumn transition was 1.02 (95% CI [0.99, 1.05], I² = 51.6%). After excluding one study with inconsistencies, the pooled RR in spring remained 1.04 (95% CI [1.01, 1.06], I² = 56.9%), while the autumn RR was 1.00 (95% CI [0.99, 1.02], I² = 17.1%).
Why it matters
This updated meta-analysis suggests a small, statistically significant increase in acute myocardial infarction risk immediately following the spring clock change, with no clear effect observed during the autumn transition.
Limits
All included data derive from observational designs prone to residual confounding. There was moderate heterogeneity among spring transition studies that persisted in sensitivity analysis, and total individual participant counts and absolute risk increases were not reported in the abstract.
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.