Abstract
Introduction: Due to the relationship between climate and human health, scientists are interested
in evaluating seasonal and daily changes in air temperature and risk for cardiovascular diseases.
Objective: The aim of this study was to investigate the relationship between seasonal temperature
changes and the rates of referring patients with acute coronary syndrome.
Patients and Methods: The present case-control study was performed on all consecutive patients
suffering acute coronary syndrome that were hospitalized in a great referral hospital in Tehran
between 2011 and 2015. The meteorological and mortality data were first matched with each
other. Then the number of patients with acute coronary syndrome was determined by region
and gender.
Results: Assessing the frequency of patients referred from 2011 to 2015 indicated the upward
trend of referral to the hospital. Regarding the frequency of referrals in different months of the
year (regardless of the year of assessment), the highest rate of referral for patients with unstable
angina was in the month of October and then in November and the lowest referral was in
August. The number of referees was significantly associated with the increase in minimum and
maximum temperature, average air pressure, as well as with the decrease in air humidity during
the years studied.
Conclusion: The risk of acute coronary syndrome attacks is highest in the cold months of the
year, especially in the autumn and early winter, and is the lowest in the middle of summer. Over
the years, increasing air temperature with increasing air pressure and reducing humidity can
increase the risk of acute coronary syndrome.