Is the increase in coronary events on Mondays an artifact?
BACKGROUND
The aim of this article was to investigate the size and possible causes of the reported excess in coronary events on Mondays.


METHODS
We conducted a metaanalysis of data from the World Health Organization (WHO) MONICA Project, which monitored trends and determinants in cardiovascular disease. The MONICA Project was undertaken in 21 countries from 1980 to 1995.


RESULTS
We found a small overall excess rate of coronary events on Mondays. In a population experiencing 100 events per week, we estimate there would be approximately 1 more event on Monday than on any other day. Hierarchical logistic regression showed that the Monday excess was greater in centers with less thorough data collection procedures.


CONCLUSIONS
The excess of coronary events on Mondays is probably an artifact resulting from events with uncertain dates being coded as taking place on Mondays.
School of Population Health, University of Queensland, Herston, Australia. a.barnett@sph.uq.edu.au
Adrian G
AG
Barnett
Annette J
AJ
Dobson
D000328:Adult; D000367:Age Factors; D000368:Aged; D000465:Algorithms; D003327:Coronary Disease / Q000453:epidemiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012042:Registries / Q000706:statistics & numerical data; D012737:Sex Factors; D013997:Time Factors