Author/Authors :
Jalali, F Department of Cardiology - School of Medicine - Babol University of Medical Sciences , Hajian-Tilaki, KO Department of Social Medicine and Health - School of Medicine - Babol University of Medical Sciences
Abstract :
The chronobiology of the acute myocardial infarction (AMI) is an interesting matter for recognition
of the biological mechanism that might trigger AMI. The
present study was aimed to investigate the circadian,
seasonal and circannual variation of the AMI occurrence
with solar, lunar, and Christian months. A retrospective
study of 1174 cases with diagnosis of AMI was conducted.
All cases included in our study were admitted to the
coronary care unit of Shahid Behashti and Yahyanejad
Hospitals in Babol, the north of Iran, between 1990 and
2000. The data was extracted by the day and month of
diagnosis based on the solar, lunar and Christian
calendar from hospital charts. The Chi-square test was
used to test the uniformity of the observed frequencies of
AMI onset in relation to the time factors based on solar,
lunar, Christian and the days of week. The results showed
that there was a significant trend toward higher rate of
MI at the beginning of the week, on the Saturday (18.1%)
and the least (12.3%) on Friday. Although, the observed
frequency of AMI tended to be higher in Ordibehesht of
solar month and Shaban in lunar month than other
months, the monthly variation was not statistically
significant (P >0.05). However, there was significant
difference in MI occurrence in Christian months with
high peak in November (P<0.05). Also, we did not found
a significant seasonal variation of AMI where 26.2%,
23.1%, 26.8% and 23.9% of MI occurred in the spring,
summer, fall, and winter respectively (P>0.05). The average number of AMI occurrence, was significantly
greater in three days of full moon phase in lunar months
than other days (P <0.05). Our results indicated a
significant day of week variation in AMI occurrence with
higher peak on Saturday and full moon phase of lunar
month. With regard the lunar and solar month variation,
more investigation, with larger sample sizes is still
necessary, but in Christian months, MI occurrence was
significantly increased in November.
Keywords :
Myocardial infarction , chronobiology , moon , solar , time factors
