Did You Know?

• Life expectancy worldwide has risen on average by 4 months each year since 1970.
• Infant mortality rates fell from 80 per 1000 live births in 1980, to 54 per 1000 in 1998.
• Women tend to outlive men by 5 to 8 years in the countries with the highest life expectancies, but by only 0 to 3 years in countries where life expectancy is low.

Life Expectancy

Map.

Life expectancy at birth is the average number of years a newborn infant would be expected to live if health and living conditions at the time of its birth remained the same throughout its life. It reflects the health of a country's people and the quality of care they receive when they are sick. Life expectancy is higher in high-income countries than in all but a few low- and middle-income countries.

Chart 1.

Between 1980 and 1998, the world's average life expectancy at birth rose from 61 to 67 years, with the most dramatic increases occurring in the low- and middle-income countries. (See Chart 1.) Increased access to nutritious food, primary health care--including safe water, sanitation, antibiotics and other medicines, and immunizations--and education explain much of the difference. It is important to note, however, that although the world's average life expectancy at birth was 67 years, individual countries can vary largely. For example, in Rwanda, life expectancy at birth in 1998 was 41 years, while in Japan it was 81 years.

Similarly, not all countries have experienced a rise in life expectancy at birth over the past two decades. Since 1980, seventeen countries--mostly in Sub-Saharan Africa and the former Soviet Union--have actually experienced a decline. In these nations, problems such as economic depression in the former Soviet Union (see Box 1) and AIDS in Sub-Saharan Africa, have overcome the progress previously made in people's living conditions. In the Sub-Saharan country of Botswana, for example, where one out of every three adults is infected with HIV, the virus that causes AIDS, life expectancy at birth decreased by fifteen years between 1987 and 1998 after it had been rising steadily for more than thirty years.

Surviving Childhood

Chart 2.

Although overall living conditions are improving and more and more infants in low- and middle-income countries are surviving, these babies are still much more likely to die within their first year than are those in high-income countries. (See Chart 2) Why? Drinking water is still often unsafe, and unsanitary conditions are still common. Pregnant women, nursing mothers, and infants may not get enough nutritious food. Family planning and other health and educational services --especially for girls--may be lacking or unaffordable. All of these factors work against the health and strength of women and their babies.

Chart 3.

Flu, pneumonia, and common diarrhea cause many deaths; so do cholera and malaria. Children, especially those suffering from chronic malnutrition, are most at risk. And many children are not immunized against deadly infectious diseases such as diphtheria, measles, polio, tetanus, typhoid, tuberculosis, and whooping cough. In some cultures where parents prefer sons over daughters, boys receive a larger share of the limited family resources. They get more food and better health care, including immunizations. As Chart 3 shows, child mortality rates--the number of children who die between ages 1 and 5 per 1,000 children--are much higher for girls in these countries than for boys, even though research shows that girls tend to have lower child mortality rates when conditions are equal.

Despite these persistent problems, efforts on the part of countries and communities around the world to improve their children's chances of survival (see Case Study) have contributed greatly to the overall increase in life expectancy at birth because life expectancy is an average. When babies and young children die, it brings down the average more than when adults die. And when more babies live into adulthood, the average usually goes up.

Living to Old Age

Children who live past their fifth birthday have a much greater chance of living to adulthood and old age because their bodies are stronger and better able to fight off the diseases that many younger children succumb to. In fact, the longer a person lives, the greater his or her chances of reaching older ages. For example, someone who has lived to 100 is much more likely to reach 101 than someone who has just reached 90, even though the 100 year old has a very high and increasing chance of dying in the next year.

Life-threatening events and personal habits, however, may reduce the chances of living a long, productive life. In fact, some countries succeeded in improving the infant and under-5 mortality rates between 1980 and 1998 but still saw a decline in life expectancy at birth. More and more, infectious diseases such as tuberculosis (the leading cause of deaths in low- and middle-income countries) and AIDS, and chronic diseases caused by smoking (see Box 2), excessive alcohol consumption, high-fat diets, and stress-related illnesses are stealing years from the lives of men and women around the world. In addition, women and adolescent girls risk early deaths due to complications of pregnancy and childbirth, especially in countries with limited medical resources or a lack of family planning, or where women's health needs are neglected.

Life Expectancy, the Economy, and the Environment

A primary goal for sustainable development is for people to live longer, more productive, more satisfying lives. This is impossible if they do not have the resources to ensure the health and well being of themselves and their families. Poverty has a major impact on life expectancy. When governments and families cannot afford enough quality health care, education, and nutritious food, people cannot reach their full potential, either in productivity or length and quality of life. In addition, extreme poverty increases the likelihood of war and political instability, which threatens lives--and the quality of life-- as well.

There are also close links between the environment and life expectancy since we depend on natural resources such as safe water, clean air, fertile soil, and fuel to sustain life. Lack of safe water is a major cause of illness and death in low- and middle-income countries, especially among children and the elderly. Polluted air from a variety of sources such as wood fires, industrial production, and car exhaust causes lung disease and associated illnesses. Areas with overworked or eroded soil may not be able to produce enough nutritious food to support growing populations. And lack of clean fuel for cooking, boiling water, or producing heat can seriously affect people's ability to thrive.

Strategies for Change: Affecting Life Expectancy

Photo 1.

Experience in many countries suggests that campaigns emphasizing the prevention of illness is one of the most effective and least expensive methods to improve public health. (See Box 3.) At the same time, education is critical because these campaigns have the greatest impact when literacy and education are widespread. Furthermore, with adequate education, people are more likely also to gain access to other key factors that help increase life expectancy such as safe water, sanitation, immunizations, medical care, and nutritious food. The education of women helps them to provide better care for their children and to pass on knowledge that will improve their children's lives. Educated women also tend to have smaller, healthier families.

Photo 1.

Immunization against infectious diseases represents another successful approach to improving life expectancy at birth. Immunization campaigns in the past 50 years successfully eliminated smallpox, and polio has disappeared in many areas. However, when countries relax immunization efforts or fail to immunize all children, infectious diseases remain a threat.

As emerging diseases such as HIV/AIDS and tobacco-related illnesses take stronger holds in low- and middle-income countries, governments and communities are having to make difficult decisions about how to use their scarce resources. The price of medical research and care for the victims of these diseases is staggering even for wealthy countries. For many, the best option is to put their efforts into education and prevention.

Life Expectancy Highlights