The greatest cause of death throughout the world today is noncommunica
ble disease. In Western societies, coronary artery disease is a princi
pal cause of death. In developing countries, the incidence of coronary
disease is rising as well. Heart disease often occurs in younger pers
ons in developing societies, resulting in a disproportionately greater
number of years of life lost. The reason for this change in global pa
tterns of mortality is that deaths from infectious diseases are declin
ing, resulting in greater life expectancy and changing lifestyles.