INCIDENCE OF CORONARY THROMBOSIS IN RELATION TO CLIMATE

To the Editor:— The observation has frequently been recorded that the incidence of coronary thrombosis is apparently increased during the cold seasons. In this connection the report by Master, Dack and Jaffe on "Factors and Events Associated with Coronary Artery Thrombosis" (The Journal, August 21) is of particular interest. These investigators analyzed more than 800 clinical attacks of coronary thrombosis in an attempt to ascertain "what factors may have initiated the thrombosis.... Excitement, ingestion of food, infection, tobacco, alcohol, heart failure, time of day and season of year were found to have no significance." Since the observation with reference to season of year is of some importance from the standpoint of both etiology and therapy, I have analyzed the data presented by Master and his associates. They divided the monthly incidence of 612 attacks of coronary thrombosis into two groups. The October-April or "autumnwinter," group comprised 314 cases, or 51.3