The primarv cause of world population growth in recent years has been a decline in mortality-the incidence of death in a population. The simplest measure of mortality is the crude death rate-the number of deaths per 1,000 people in a population in a given year. In 2005 the U.S. crude death rate was 8.3 per 1.000 (U.S. Census Bureau, 2009). In high-income. developed nations, mortality rates have declined dramatically as diseases such as malaria. polio. cholera. tetanus. typhoid, and measles have been Virtually eliminated by vaccinations and improved sanitation
and personal hygiene (Weeks. 2008). lust as smallpox appeared to be eradicated, however, H IVIAIDS rapidly rose to surpass the 30 percent fatality rate of smallpox.
(1l1C ten leading causes of de th in the United States arc shown in • Table 19.1.) In low-income, lessdeveloped nations. infectious diseases remain the leadingcause of death; in some areas. mortality rates arc rapidly increasing as a result of HI VIA IDS. Children under age 15 constitute a growing number of those who are infected with Hrv. But many children do not’survivc long enough tocontract communicable diseases. On a global basi;” large numbers of newborn infants do .not live to see
their first birthday. The measure of these deaths is re (erred to as the infant I/Iorl,llily rate, which is defined in Chapter 18 as the number of deaths of infants under I year of age per 1.000 live births in a given year. The infant mortality rate is an important reflection of a soddy’s level of preventive (prenatal) medical care. maternal nutrition, childbirth procedures. and neonatal care for infants. Differential levels of access to these services are reflected in the divergent infant mortality rates for African Americans and whites. In 2005. for example. the U.S. mortality rate for white infantswas 5.7 per 1.000 live births. as compared with 13.7
pcr 1.000 live births for African American infants (U.S. Census Bureau. 2(09). This constituted a decrease in infant mortality rates for African Americans. which were at a high of 22.2 in 1980 and remained in the 14 to IS category until 2004. when the rate dipped to U.8 per 1.000 live births. As discussed in Chapter 18. life expectancy is an estimate of the average lifetime in years of people born in a specific year, For persons born in the United States in 2008, for example, lift: expectancy at birth was 78.1 years. as compared with 82.1 years in Japan and 50 years or less in the African nations of Nigeria. Somalia. and South Africa (U.S. Census Bureau. 2009). Life expectancy varies by sex; for instance. females born in the United States in 2010 can expect to live almost 81 years as compared with 75.7 years for males. Life expectancy also varies by race. As we noted in Chapter. 18. life expectancy for African American males born in 2010 is estimated at 70.2 years as compared to 77.2
for African American females and 75.7 year” for while males (U.S. Census Bureau, 2009).