Major Causes of Death in the United States and Peru .gif)
* Includes diarrhea and inflammation of the stomach and intestines.
** Primarily influenza, bronchitis, and pneumonia.
Source: Pan American Health Organization,
Health in the Americas 2 (1998); and National Center for Health Statistics,
National Vital Statistics Reports 47, no. 19 (June 30, 1999).
Teachers Guide
Question and Answer: Does AIDS have a significant impact on population growth?
Declining mortality, not rising fertility, has been the cause of the accelerating pace of world population growth. By attacking the causes of death that have kept population growth low for most of human existence, we have extended life expectancies and multiplied our numbers.
Life expectancy has increased steadily through history. During the Roman Empire, average life expectancy at birth was a brief 22 years. By the Middle Ages it had risen to about 33 years in England, and increased to 43 years by the middle of the 19th century. In the early 1900s, life expectancies in more developed countries ranged from 35 to 55. They have climbed to about 75 years today, and continue to improve. Meanwhile, life expectancy in less developed countries has gradually climbed, rising to about 64 years in 1995.
Initial declines in mortality can be attributed to improvements in public health and living standards that accompanied the Industrial Revolution. Greater declines in the early 20th century were attributable to improvements in medical technology, which led to the control of such infectious diseases as tuberculosis, smallpox, and cholera. Further improvements in life expectancy are anticipated in most countries. In countries where death from infectious diseases is minimal, the improvements will come from the decline in mortality from degenerative diseases such as heart disease and cancer. In some countries, the spread of AIDS and other infectious ailments is a potential threat to further gains in life expectancy. In Central Africa, where the spread of HIV infection is disproportionately high, life expectancy has begun to decline.
Deaths to Children under Age 5 by Main Cause, Less Developed Countries, 1995
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Source: UNICEF, The State of the World's Children, 1998.
Infant and Child Mortality
In less developed countries, the chances of dying are greatest at infancy and remain high during the first few years of childhood. A newborn child is fragile and has not developed immunities to common ailments. When a country has a high rate of infant death, it usually signals high mortality risk from infectious, parasitic, communicable, and other diseases associated with poor sanitary conditions and malnourishment. As a result, the infant mortality rate (IMR), or annual number of deaths of children under age 1 per 1,000 live births, is considered one of the most sensitive measures of a nation's health.
World Infant Mortality Rates in Selected Countries, 2000
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Source: Carl Haub and Diana Cornelius, 2000 World Population Data Sheet (Washington, DC: Population Reference Bureau, 2000).
Worldwide about 8 million babies die annually before their first birthday. As the chart "Deaths to children under age 5 by main cause" indicates, two of the primary causes of infant and child deaths are acute respiratory diseases — such as pneumonia, tuberculosis, and influenza — and diarrhea. Other infectious diseases, such as measles, are also major causes of deaths to infants and children. Death from these conditions is almost unheard of for infants in more developed countries. But in less developed countries where malnourishment weakens small bodies, medical facilities are scarce, and living areas may be unsanitary, infant deaths are common. In 2000, world IMRs range from 2.6 per 1,000 births in Iceland to 157 per 1,000 in Sierra Leone.
As countries develop economically, infant mortality usually declines. The IMR in the United States was probably about 100 in 1900 — around the level of the IMRs of some of the poorest countries in the world today. The IMR in the United States has now fallen to below 10. Many countries have even lower rates, with Japan, Sweden, and Finland heading the list (see "World Infant Mortality Rates in Selected Countries").
Causes of Death
The chart "Major causes of death in the United States and Peru" is useful for developing a better understanding of the changes in mortality in this century. It shows the major causes of death for the United States in 1900 and 1997, and for Peru in 1992. Each column accounts for all causes of death with the top causes specified. Some causes are combined because of their similarities. Data on cause of death should be interpreted cautiously because some causes are more easily identified than others and are reported more completely.
In the United States in 1900, respiratory, infectious and parasitic, and gastrointestinal diseases (including diarrhea) accounted for nearly 40 percent of all deaths. Since then, mortality rates from these diseases have declined sharply. For example, tuberculosis, which accounted for 11 percent of deaths in 1900, accounted for less than 1 percent in 1997. Heart diseases, stroke, and cancer, which account for more than half of all deaths today, caused only about 15 percent of deaths in 1900.
In Peru today, like the United States in 1990, the causes of death are more broadly dispersed. Fifty percent are attributable to the top four causes. Respiratory diseases top the list, with cancer, digestive, and heart diseases also contributing a large share.
As Peru and other countries continue to develop, their causes of death may more closely resemble those of the United States today. As life expectancy improves and the role of infectious, parasitic, and respiratory diseases diminishes, more people will survive to older ages and chronic degenerative diseases such as stroke, cancer, and heart disease will become more common causes of death.
Terms
Infant mortality rate (IMR): The number of deaths of infants under age 1 per 1,000 live births in a given year.
Less developed countries: Less developed countries include all countries in Africa, Asia (excluding Japan), and Latin America and the Caribbean, and the regions of Melanesia, Micronesia, and Polynesia.
Life expectancy: The average number of additional years a person of a given age could expect to live if current mortality trends were to continue for the rest of that person's life. Most commonly cited as life expectancy at birth
More developed countries: More developed countries include all countries in Europe, North America, Australia, New Zealand, and Japan.
Mortality: Deaths as a component of population change.