The potential influence of lunar phases on the occurrence of myocardial infarction is still controversial. The purpose of the present study was to investigate the association of the lunar cycle on the occurrence of fatal and non-fatal myocardial infarction based on a myocardial infarction registry.Methods and results:
We studied 15,985 patients consecutively hospitalised with an acute myocardial infarction (AMI) between 1 January 1985 and 31 December 2007 with a known date of symptom onset who were recruited from a population-based myocardial infarction registry. The exact hour of AMI onset was known for 9813 events. Poisson regression analysis was performed to examine the relation between the lunar cycle and the occurrence of AMI. There was no association between new moon, full moon, waning moon and waxing moon and the occurrence of AMI. However, we observed that the three days after a new moon may be significantly protective for the occurrence of AMI, rate ratio (RR) 0.94 (95% CI 0.91-0.98), and the day before a new moon had a slightly negative effect (RR 1.06, 95% CI 1.00-1.12). Stratified analysis did not reveal any susceptible subgroups.Conclusion:
The moon phases did not show any apparent association with AMI occurrence. However, there might be a ‘cardioprotective’ time three days after a new moon.