Daylight savings time and myocardial infarction.
Level 3 - non-randomized controlled study
Retrospective time-series study of a multicenter clinical registry cohort
PubMed 25332784 · doi:10.1136/openhrt-2013-000019
What was done
The authors analyzed acute myocardial infarction (AMI) admissions undergoing percutaneous coronary intervention (PCI) recorded in the Blue Cross Blue Shield of Michigan Cardiovascular Consortium (BMC2) database between March 2010 and September 2013. They evaluated daily and weekly event counts during the weeks following four spring and three fall Daylight Saving Time (DST) changes, using a negative binomial regression model adjusted for background trend and seasonal variation.
What was found
There was no significant difference in the total weekly number of PCIs performed for AMI after either spring or fall time changes. After adjustment for trend and seasonal effects, the Monday following the spring transition showed a 24% increase in daily AMI counts (p=0.011), while the Tuesday following the fall transition showed a 21% reduction in daily AMI counts (p=0.044). No other individual weekdays in the post-DST weeks showed statistically significant changes.
Why it matters
The findings suggest that DST transitions shift the acute timing and presentation pattern of AMI within the subsequent week rather than altering total weekly incidence.
Limits
The abstract does not state the total sample size (n of patients or PCIs). The analysis was limited to patients undergoing PCI within a single state registry, omitting AMI cases managed medically or out-of-hospital deaths, and observational time-series data cannot prove direct causality.
Cited by
- context In the three days following the spring transition into daylight saving time, heart attacks increase by an average of 24% across 70 countries.
- partial When falling back for daylight saving time and gaining one hour of sleep, heart attacks decrease by 21% across countries that observe it.