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 These have been replaced by chronic diseases; heart disease, cancer (malignant neoplasms), and stroke (cerebrovascular diseases) were the three leading causes of death in 2001. (See Table 4.1.)
In 2001 the age-adjusted death rate (which accounts for changes in the age distribution of the population across time) for heart disease was 247.8 deaths per 100,000 people, while that for cancer was 196.0 per 100,000 persons. (See Table 4.1.) Together, these two diseases accounted for 51.9 percent of all deaths in the United States. 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 aged 1 to 34 years, accidents and their adverse effects were the leading causes of death during the period from 1999 to 2001. For those aged 35 to 44 years, cancer was the leading cause of death during this time period, with accidents and their adverse effects second, and heart disease third. Cancer and heart disease account for most deaths among those 45 years and older. (See Table 4.2.) The Institute of Medicine of the National Academies reports that heart disease, cancer, and stroke "disproportionately affect older people"—those 65 years of age and over, a view 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 2002, with a slight upturn in 2001. (See Table 4.3.) From 1999–2002, 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, experience more AIDS deaths 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.