Mani Mofidi, Seyed Yaser Foroghi Ghomi, Mansoureh Shakeri
Background & Aim: Iran is among countries implementing daylight saving time (DST) according to its Constitution every year. The impact of this time change on the incidence of acute heart attack has been investigated in several countries, indicating an increase in the incidence of acute heart attack on days after time change. In this regard, the present study was carried out given that DST is annually implemented in Iran and no research has been done on the effect of time change on the incidence of heart attack so far.
Methods & Materials: In this analytical cross-sectional study, 125 patients with heart attack symptoms visiting the emergency department of the hospitals affiliated to Tehran University of Medical Sciences (TUMS) were investigated. These patients experienced acute heart attack 7 days after time change (i.e., from March 20, 2012), 14 days before time change (i.e., from March 6 to March 19, 2011), and 14 days after time change (from March 27 to April 10, 2012), as well as in autumn (from September 22 to September 28, 2012 and 14 days before and after this date). The data were collected from patients’ records admitted to the hospitals affiliated to TUMS and then statistically analyzed.
Result: The total number of patients visiting the emergency departments of the hospitals affiliated to TUMS within 5 weeks around March and 5 weeks around September was 9699. The results of this study showed no significant difference between the number of patients with acute heart attack in the week after time change and their number during the 14 days before and after time change in spring and autumn (p>0.05). Moreover, although the rate of heart attack during the days of the first week after time change was higher than the similar days in the other 4 weeks, the difference was not statistically significant (p>0.05).
Conclusion: Although the results of the present study showed no correlation between DST in Iran and the incidence of acute heart attack, previous studies have shown the disrupting effect of DST on the circadian rhythm and consequently, on the cardiovascular function in humans. Therefore, it is necessary to conduct further studies.
