Associations between Ambient Temperature and Acute Myocardial Infarction.

Background: The associations between incidence of acute myocardial infarction (AMI) and the ambient temperature were mixed in prior studies.

Methods: Data of 2033 consecutive admissions of AMI in a central tertiary hospital in North China from 1st Jan 2003 to 31st Dec 2011 were collected. The weather data in this period were from the local meteorological department. Based on the ambient temperature information, we defined several ambient temperature indices, including daily average temperature, extremely low temperature, and daily temperature range, then characterized the independent associations between them and the incidence of AMI.

Results: The daily average temperature one day before was independently associated with AMI incidence rate: a rise of 5°C of the daily average temperature led to a 5% decrease in AMI admissions. Daily average temperature and temperature range two days before were independently associated with AMI incidence rate: a rise of 5°C of the daily average temperature led to a fall of 6% in AMI admissions, and a rise of 2°C of the daily temperature range led to a rise of 4% in AMI admission.

Conclusion: Low ambient temperature has substantial association with AMI, and can play an important role in warning and forecasting the incidence.