The “Merry Christmas Coronary” and “Happy New Year Heart Attack” Phenomenon

Abstract

In 1999, my research group published a study that examined whether there are seasonable variations in cardiac mortality in a location where winter weather is mild—Los Angeles County, Calif.1 During a 12-year period, there were consistently more deaths from ischemic heart disease during the winter than there were during the summer. About one third more deaths from ischemic heart disease were recorded in December and January than from June through September in Los Angeles County. We initially thought that this phenomenon might be explained by colder temperatures. Colder temperatures have been associated with an increase in vascular resistance, coronary vasospasm, blood pressure, and hemostasis, as reviewed by Spencer et al.2 Temperatures in Los Angeles during the winter, although colder than they are during the summer, are still mild as compared with other climates. When we plotted daily rates of death from ischemic heart disease in Los Angeles County during November, December, and January, we were struck by an increase in deaths starting around Thanksgiving, climbing through Christmas, peaking on New Year’s Day, and then falling, whereas daily minimum temperatures remained relatively flat during December and January. We postulated that this peak in cardiac deaths during the holidays might result from other factors, including the emotional stress of the holidays, overindulgence during the holiday season, or both.1 See p 3781 The study by Phillips and coworkers3 in this issue of Circulation is an important contribution that extends our initial observation of an increase …