Cold weather and myocardial infarction.

We studied 1217 cases of myocardial infarction, admitted to Patna Medical College Hospital, Patna, during the period 1979 to 1983, and correlated the incidence of the disease with air-temperature, seasons and months. There was no monthly variation in the incidence of the disease. The seasons similarly had no influence on incidence. The frequency of myocardial infarction, however, was significantly higher when the minimum air-temperature was 16 degrees C or less (P less than 0.001). This study indicates that drop in atmospheric temperature below a certain level directly increases the incidence of myocardial infarction and suggests simple prevention measures against the adverse effect of cold.