A drop of 1°C on a single day may be associated with an extra 200 cases of MI, a BMJ study showed.
While ambient outdoor temperature has been shown to affect short term mortality risk, little is known about the affect on MI risk.
Researchers from the London School of Hygiene and Tropical Medicine studied 84,010 hospital admissions for MI from 2003 to 2006 and cross-checked these figures with daily temperature readings.
Results were adjusted to account for air pollution, influenza activity, seasonality and long term trends.
They found that a 1°C reduction in average daily temperature was associated with a cumulative 2% increase in risk of heart attack for 28 days after the drop. The highest risk was within two weeks of exposure.
They noted that those receiving aspirin were less vulnerable to MI, reinforcing ideas that the effect ‘may be mediated by changes in platelet function’.
The authors suggest that an early warning system based on forecasted weather could be established to warn at-risk groups to stay warm and watch for symptoms.