During the twentieth century the primary causes of death in the United States changed. In the 1800s and early 1900s infectious (communicable) diseases such as influenza, tuberculosis, and diphtheria were the leading causes of death. These have been replaced by chronic diseases; heart disease, cancer (malignant neoplasms), and stroke (cerebrovascular diseases) were the three leading causes of death in 2003. (See Table 4.1.)
In 2003 the age-adjusted death rate (which accounts for changes in the age distribution of the population across time) for heart disease was 232.3 deaths per one hundred thousand people, while that for cancer was 190.1 per one hundred thousand persons. (See Table 4.1.) Together, these two diseases accounted for 50.7% of all deaths in the United States in 2003. Deaths from heart disease have been decreasing since 1950, while cancer mortality has been dropping only since 1990.
Not surprisingly, the leading causes of death vary by age. For those ages one to forty-four, accidents and their adverse effects were the leading causes of death in 2002 and 2003, as well as the leading cause of death for those ages one to thirty-four in 1999, 2000, and 2001. For those ages thirty-five to forty-four, cancer was the leading cause of death in 1999, 2000, and 2001, with accidents and their adverse effects second, and heart disease third. Cancer and heart disease caused most deaths among those forty-five years and older from 1999 to 2003. (See Table 4.2.) The Institute of Medicine of the National Academies reports that heart disease, cancer, and stroke "disproportionately affect older people"—those sixty-five years of age and over, which is supported by the figures in Table 4.2.
According to an HIV/AIDS Surveillance Report begun in 1993, 1996 marked the first year a decline occurred in U.S. deaths due to AIDS. This downward trend in annual numbers of deaths due to AIDS continued from 1998 through 2000. From 2001 to 2003 the number of cases increased and plateaued with slightly higher numbers of total deaths. (See Table 4.3.) In 2004 the number of deaths from AIDS decreased. From 2000 through 2004 most males with AIDS contracted HIV via male-to-male sexual contact or injection drug use. Most females contracted the virus by heterosexual contact or injection drug use. Children most often contracted the virus perinatally (immediately before and after birth) from infected mothers. The South and the Northeast, respectively, experienced more AIDS deaths during these years than other parts of the United States.
AIDS, the final stage of HIV infection, has had a tremendous effect on society. This epidemic has brought a painful, drawn-out process of dying to many, including young adults—an age group previously relatively untouched by death, particularly from infectious disease.