Seasonal variations in the occurrence of acute myocardial infarction in Hungary between 2000 and 2004.

Background: The purpose of this study was to determine whether a weekly or seasonal variation could be observed in the onset of acute myocardial infarction (AMI).
Methods: A retrospective analysis of patients diagnosed with AMI between 2000 and 2004 in Hungary (n=81,215 patients) was carried out. Data were collected by the National Health Insurance Fund Administration (OEP). We calculated the number of AMI cases (incidence) per year, month, and per day in the course of a week with 95% confidence interval. Statistical analysis using one-way analysis of variance (ANOVA) was performed.
Results: A peak period of the occurrence of AMI was found during spring, while minimum number of events were recorded during summer. Significant difference was observed between the number of events each season (F=34.741; p<0.001). Between 2000 and 2004 the monthly occurrence of AMI was highest in March, May and October (F=11.658; p<0.001). The weekly peak period of AMI morbidity was found on the first day of the week, showing a gradually decreasing tendency all week-through, reaching its minimum incidence on Sunday (F=4.162; p<0.001).
Conclusions: Results of our study reveal that the incidence of AMI shows a characteristic rhythm with respect to seasons and the days of the week, which should be considered in the development of preventive concepts.