Reproduced with permission,
People are a precious, yet often neglected, resource. To a large extent this is because their sheer numbers strain the systems designed to serve them. The world population has doubled in the past 40 years and may double again in the next century, perhaps approaching stability at about 11 billion by the year 2100. Most of this increase will take place in the developing world. Without a great deal of effort and ingenuity, many of these new citizens will degrade natural resources and not be offered the healt h and educational resources necessary to reach their potential.
Humanitarian concerns aside, building a healthy, educated, stable population makes economic sense and is a chief component of sustainable development. (See Chapter 1, "Dimensions of Sustainable Development.") The newly industrialized countries---Asia's fo ur tigers---made remarkable economic progress by developing an educated workforce as the basis for a manufacturing boom. Short on natural resources, South Korea, Singapore, Hong Kong, and Taiwan used their human resources to bound out of poverty. Other de veloping countries are following suit; ideally, they will avoid some of the environmental pitfalls experienced by Asia's tigers. (See Chapter 4, "Sustainable Development Case Study: Rapidly Industrializing Countries.")
In its recent series of Human Development Reports, the United Nations Development Programme has asserted that although economic development generally improves the well-being of a population, other factors are also important---specifically, increased schoo ling and health care. This gives hope to low-income countries and countries suffering economic stagnation that they can improve their citizens' lives by directing limited financial resources into primary education and health care programs.
Of the roughly 37 million people who died in developing countries annually in the mid-1980s, almost 37 percent were children. This shocking figure compares to developed countries where only 3 percent of the annual deaths are of children. Mortality figures ---used as the most reliable measure of health---show only the most severe cases of ill-health and do not indicate a much larger population of sick, malnourished, and listless children. Most of these children are sickened by diseases that can be easily pr evented or cured with proper sanitation, nutrition, and vaccines. However, these basic needs are still unavailable to many children in developing countries. Striking progress has been made in vaccinating children and in providing simple treatment for diar rhea, the biggest cause of death among children of the developing world. (See Focus On Children's Health, below.)
Although it might seem that reducing child mortality would increase population growth, the opposite is the case if countries also develop economically. As countries develop, they go through a process called demographic transition in which living standards are raised, child mortality is reduced, and fertility declines. This transition can be speeded by policies that promote education, health care, and use of contraceptives.
Global Trends
The different prospects for the industrialized and developing countries are nowhere more evident than in their respective population sizes. By 1990, of the world's 5.3 billion people, 4.1 billion---77 percent---lived in the developing world; 1.2 billion i nhabited the industrialized countries. (See Table 6.1.)
The difference in growth rates of developing and industrialized countries is even more dramatic. Population growth in the industrialized countries has been relatively modest, rising about 15 percent over the 1970-90 period. In those same two decades, the population of developing countries grew by almost 55 percent, from 2.65 billion to 4.1 billion. The disparity in numbers will widen by 2025, when population in industrialized countries is projected to be 1.35 billion and 7.15 billion in developing countri es (or about 84 percent of world population).
This burst of population growth in the developing world is easily explained. Before World War II, both birth rates and death rates were high in these countries, which kept growth low. Since then, rapid improvements in health care and sanitation have cause d death rates to plummet, while birth rates have remained high.
Large differences in the age structure of populations in the industrialized and developing worlds help account for the projected widening of the population disparities. In the industrialized countries, the proportions of people in each age range are rough ly equal, with a slight bulge among the postwar baby-boom generation, which is now 30-45 years old. In the developing countries, far more people are in the young age groups, which will swell the number of children born each year as the increasing number o f young women of childbearing age have children. (See World Resources 1990-91, pp. 51-55.)
Declining Growth Rates, Increasing Numbers
For several decades, population planners have focused on reducing population growth rates in developing countries. In many regions, that effort has been relatively successful, as Figure 6.1 suggests; the major exception has been Africa, where growth rates since the mid-1960s have increased.
Declining birth rates, however, belie the immense momentum already built into the system; that is, each woman is having fewer children, but many more women are giving birth. By the year 2000, over 90 million people---more than Mexico's current population- --will be added annually to the population of the developing countries (1). (See Figure 6.2.) Thereafter, the number of people added each year will decrease slowly with world population probably stabili zing at a projected 11.2 billion in 2100 (2).
Fertility and Contraception Trends
As Figure 6.3 indicates, total fertility rates in the industrialized countries have remained roughly at or below 2 during the 1980s and into 1990. (The fertility rate is the average number of children women bear in their lifetim e.) Within Asia, the experience has been varied. Largely because of China's strong population control programs, which resulted in a total fertility rate of 2.3, rates in East Asia have declined dramatically over the past four decades. Some countries in So uth and Southeast Asia--especially Singapore, Thailand, Indonesia, Sri Lanka, and India---also have made significant progress. Fertility rates in Latin America followed a similar path, but rates in Africa have remained virtually unchanged since the 1950s (3).
With large numbers of women now in or entering their reproductive ages, the downward trend in birth rates will be enormously difficult to maintain. Population assistance programs can play an important role in developing countries. Because of past investme nts in population programs, the world already has 400 million fewer people than it other wise would, according to one study, and will have 4 billion fewer people during the next century than it would have had without such programs (4 ).
Increased access to effective contraception has been an important factor in fertility declines in developing countries, most notably in Asia and Latin America. In China, an estimated 71 percent of married women are using contraception, a figure that match es the rate in Europe and is far higher than the estimated 44 percent rate in the rest of the developing world. Contraception also is now widely used among married women in rapidly industrializing countries such as Thailand (68 percent), Republic of Korea (77 percent), Taiwan (78 percent), and Brazil (66 percent). It is still rarely used, however, in many African countries (5). (See Figure 6.4.)
Investments in the welfare of women can have a striking impact on population and health trends. In Thailand, female literacy has reached 90 percent, while the fertility rate has declined significantly, and the population growth rate has dropped to 1.5 per cent a year. (See Chapter 16, "Population and Human Development," Tables 16.1 and 16.5.) Investments in family planning and health services also can greatly benefit women: in Nicaragua, Sri Lanka, Bots wana, and elsewhere, government efforts to encourage participatory, community-based health programs have helped to reduce maternal mortality substantially (6).
Some governments have begun to recognize that men are an important audience for family planning information and education. The Republic of Korea began to focus on men in the 1970s, and the number of men taking responsibility for family planning has risen dramatically since then (7).
The broadest measures of human health---life expectancy at birth and mortality among children under age 5 and among infants under age 1, for example---show improvement in all developing regions (although not all countries) over the past few decades. Reduc tions in under-five and infant mortality have been impressive in all regions; both have dropped by about one third in developing countries as a whole. (See Tables 6.2 and 6.3.)
In absolute terms, nevertheless, stark contrasts remain in the health prospects of people living in the world's poorest and richest nations. In Africa, mortality of children under 5 is now roughly 147 per 1,000 live births, which is nearly 15 times higher than the rate in the United States and Canada (8).
Environmental pollutants pose hazards to human health. Human exposure to chemical contaminants in food, indoor air pollutants, hazardous wastes, and ionizing radiation all have significant health effects throughout the world. Moreover, in the developing w orld, malnutrition, inadequate water supplies and sanitation, poor hygienic practices, and overcrowded living conditions all contribute to the incidence of diarrheal and infectious diseases.
Chemical, industrial, and nuclear accidents pose potentially serious health hazards. The most tragic recent examples have been the chemical accident at Bhopal, India, and the nuclear accident at Chernobyl in the Soviet Union. Overall, it is estimated that more than 200 serious chemical accidents occur annually in the industrialized countries alone (9).
Acute pesticide poisonings are a major health problem in developing countries. The World Health Organization (WHO) estimates that worldwide each year there are more than 1 million accidental acute pesticide poisonings and more than 20,000 accidental death s. An additional 2 million cases and 200,000 deaths are thought to be suicides rather than accidents
Major Causes of Death and Disease
On a global level, about 48 million people died annually during the mid 1980s, including about 11 million in the industrial world and about 37 million in the developing world. Three fourths of all deaths in the industrial world were caused by diseases of the circulatory system (54 percent) and cancer (21 percent) (11) (12).
Statistics on causes of death in developing countries are often unavailable or unreliable. Using available data and indirect methods, WHO has estimated that of the nearly 37 million people (23.3 million adults and 13.5 million children) who died in develo ping countries in 1985, 44 percent (16 million) died of infectious and parasitic diseases (13). (See Table 6.4.)
Deaths of Children
Of those who died annually in developing countries around 1985, almost 37 percent (13.5 million) were children under age 5 compared to about 3 percent in industrialized countries (14) (15). For 1990, W HO estimated that about 12.9 million children were dying annually in developing countries. Infectious and parasitic diseases in 1990 killed about 9.8 million children before their fifth birthday. The most common causes of death in developing countries are respiratory infections, neonatal and perinatal complications, and diarrhea (16).
Cancer and AIDS
There has been less progress, and occasionally regression, in the fight against some diseases. For example, cancer, which causes more than 20 percent of the deaths in industrialized countries, is increasing primarily because of an increase in the average age of the population, improved control of other health problems, and increased use of tobacco (17). Acquired immune deficiency syndrome (AIDS), first recognized in 1981, has rapidly become a major global health problem. AIDS is caused by the human immunodeficiency virus (HIV). Some 15-20 percent of all those infected are expected to develop AIDS within 5 years; within 10 years, about 50 percent of those infected will develop the disease. By early 1990, an estimated 5-10 million people were infected with HIV worldwide---about half in sub-Saharan Africa and half in Europe and North America---and about 600,000 clinical cases of AIDS had occurred in adults. The number of cases was expected to reach 1 million by the end of i991 and several million by the end of the century (18).
Vector-Borne Diseases
Many vector-borne diseases---those carried by other organisms---are pervasive problems in some regions of the developing world. The most serious diseases include malaria, schistosomiasis, and other diseases such as lymphatic filariasis, and onchocerciasis .
Key Issues
The United Nations Development Programme embarked in 1990 on a new effort to measure human development that emphasizes progress in human health and literacy. The centerpiece of the Human Development Report 1990 and Human Development Report 1991< /i> is the human development index, which ranks countries using a combination of three indicators---life expectancy, literacy, and living standards as measured by gross domestic product per capita. The report asserts that while economic growth is a critic al component of human development, it does not capture the broader picture of human welfare. Programs that translate economic growth into education and health care are essential to produce a better life for a nation's people (27 ).
The 1991 report adjusted the index slightly by broadening the literacy factor to include mean years of schooling (28). In addition, separate indexes were prepared for:
The index reveals that some countries---Sri Lanka, Chile, Costa Rica, Jamaica, Tanzania, and Thailand, among others---seem to have been far more successful than others in translating economic progress into broad welfare gains for their people.
In assessing the various country cases, the 1990 report came to several conclusions:
The 1991 report suggests ways to improve human development efficiently. In health care, for example, governments could make large savings by using the least expensive treatments rather than high-tech alternatives, buying generic rather than brand-name dru gs and purchasing them through competitive bidding, improving the storage and distribution of drugs, and employing health-care personnel with fewer formal qualifications (31).
The threat to human health posed by environmental deterioration was dramatically evident in early 1991, when, for the first time in this century, a cholera epidemic struck six countries in Latin America. Several African countries were also plagued with th is disease. As of late September 1991, the World Health Organization had received reports of 300,000 cases of cholera and 3,200 deaths, primarily in Peru and to a lesser extent in Ecuador, Colombia, Mexico, Guatemala, and Brazil (32 ). Worldwide, the number of new cases of cholera (177,000) in the first four months of 1991 nearly equaled the total for all of 1971, when a cholera pandemic was at its peak in Africa and Asia (33). By late 1991, the epidemi c in Latin America appeared to be stabilizing. However, the arrival of warmer weather could cause a resurgence in affected countries as well as the spread to countries previously unaffected (34). In Africa, the disease continued to sweep through The Gambia, Nigeria, Ghana, and other West African countries, with more than 45,000 cases and nearly 3,500 deaths reported (35).
Cholera is an acute intestinal infection caused by Vibrio cholerae bacterium. The first cases in Latin America were reported in Peru in January 1991, appearing almost simultaneously in communities along a 1,200 kilometer length of coastline (36). The bacterium responsible for the world's outbreak was of the same bio-type (El Tor) that started the seventh pandemic in 1961, spreading through Asia and the Middle East in the 1960s and invading West Africa in 1970 (37).
Cholera is transmitted primarily through contaminated water and food, especially raw vegetables and seafood. It can spread rapidly, especially in overpopulated communities with poor sanitation and unsafe drinking water. Children are particularly susceptib le to the disease (38).
The outbreak in Peru is a side effect of the rapid urbanization of the country together with a proliferation of crowded urban slums that lack adequate safe water and sanitation facilities. People living in these slums typically are poorly educated and poo rly nourished, with little access to medical and health services. Cholera is treatable with oral rehydration salts, but the ultimate solution in countries such as Peru requires improvements in water and sanitation, health and education, and food safety (< a href="#fn39">39).
The 1.7 billion children under age 15 who inhabit the earth today represent one third (32 percent) of the planet's population; 82 percent of these children (1.4 billion) live in the developing world. Moreover, during the 1990s, the largest generation ever will be born, with nearly 90 percent of the expected 1.5 billion births to occur in developing countries (40). These are the same countries in which large numbers of children still die needlessly from malnutrition and disease c aused by inadequate drinking water. poor sanitation, and other environmental ills. Nearly all deaths of children under age 5 (97 percent) and maternal deaths (99 percent) are in developing countries (41) (42) (43).
The environmental conditions in which these children live pose a serious threat to their current health and future prospects (44) (45). As the most fragile members of society, they are most vulnerable to disease and environmental stress; their long-term well-being depends on the sustained ability of the Earth's resources to support this still expanding population.
At a rhetorical level, recognition is growing that societies have responsibilities not only to their current citizens, but to future ones as well. At the World Summit for Children, held at the United Nations in September 1990, leaders from 71 countries co mmitted themselves to "promoting the survival, protection, and development of the present generation of children and all generations to come" (46). For those concerned about sustainable development, the concept of "intergenerati onal equity" suggests that the welfare of future generations---including the children already born---should be an implicit consideration in today's decisionmaking (47). Despite the rhetoric, however, the economic, social, and en vironmental conditions in which many children live put them at serious risk for ill health, malnutrition, life-long disability (both physical and mental), and early death.
Progress has been made. Worldwide, the annual number of deaths of children under 5 declined by 4.7 million between 1965-70 and 1985-90. Developing countries have improved their children's health considerably. Between 1965-70 and 1985-90, the infant mortal ity rate declined by 33 percent in developing countries, from 116 per 1,000 live births to 78. (See Table 6.3.) The mortality rate of children under 5 years of age shows a similar trend: a 35 percent reduction, from 184 to 119 d eaths per 1,000. Under-five mortality in industrialized countries during this time period dropped 47 percent, but the number of deaths per 1,000 was already far lower, dropping from 32 to 17. (See Table 6.2.) In the developing w orld, 37 percent of total deaths are children under 7; in the developed, 3 percent (48) (49). A baby born in a developing country today is seven times more likely to die before its first birthday than one born in the industrialized countries. Among developing countries, disparities in child mortality have widened; in the early 1960s, the differences between the best and worst rates were 7 to 1; by the early 1980s, they had increased to 15 to 1 (50). Unfortunately, recent reports show that progress in children's health has slipped in the United States. (See Box 6.1.)
In the developing world, 12.9 million children under age 5---more than 35,000 a day---died in 1990 of diseases, most of which were once as common in developed countries (51). In other words, these children are dying of diseases for which effective means of prevention, as well as effective treatments, are available. (See Figure 6.5.)
Acute Respiratory Infection
Respiratory infections are responsible for some 4.3 million childhood deaths annually. About 17 percent of these deaths are a consequence of pertussis (whooping cough) and measles and are thus preventable through immunization; the vast majority---roughly 75 percent---are caused by pneumonia (52).
In the developed world, most children recover from pneumonia; in developing countries, they often do not. In Guatemala, the mortality rate among infants due to influenza and pneumonia is estimated to be 1,000 per 100,000 live births; this is 8 times highe r than Argentina (120 per 100,000), 10 times higher than Cuba (97 per 100,000), and 125 times higher than Canada (8 per 100,000) (53).
One important contributing cause to acute respiratory infections (as well as to other diseases) in children are the particulates released when wood and animal dung are used to fuel traditional stoves. (See Chapter 13, "Atmosphere and Climate.") WHO estima tes that 400-500 million people (including many women and young children) are affected worldwide, with rural homes having levels of particulate pollution ranging from 300 to 14,000 micrograms per cubic meter. The WHO maximum recommended level is 100-150 m icrograms (54)
Bacterial pneumonia occurs far more frequently in developing countries than viral pneumonia (representing two thirds to three quarters of pneumonia cases), making oral antibiotics the treatment of choice (55). Because their admi nistration has been considered the preserve of medical doctors, antibiotics have been difficult to dispense widely in developing countries. But as a result of a series of pilot studies, WHO estimates that deaths from acute respiratory infections can be re duced by at least 30 percent if community health workers are trained in a standard protocol that involves dispensing antibiotics when certain clear indicators are present (56) (57) ( 58). There already is some evidence of improvement; WHO estimated that respiratory infections claimed 4.3 million children in 1990, down about 10 percent from the 1985 estimate of 4.8 million (59).
Diarrhea
In almost every developing country, diarrhea and respiratory infection are the first and second most common causes of illness and death among children under 5 years old (60). Diarrheal disease causes about 3.2 million child deat hs annually (61). In some countries, children suffer an average of eight or nine diarrheal episodes a year (compared with a global average of three per child per year) (62). As much as 13 percent of a child's life may be spent ill with diarrhea. Repeated and prolonged bouts contribute to undernourishment, which in turn increases the severity and duration of future diarrheal episodes (63).
The most serious aspect of diarrhea is the dehydration that usually accompanies it---a condition that can be prevented if parents and health care workers have access to, and know how to use, oral rehydration therapy (64). In thi s simple technique, vital fluids and ions lost during diarrheal episodes are restored through the administration of either a prepared packet of oral rehydration salts (ORS) or a home-prepared solution. Oral rehydration has been called one of the most impo rtant medical breakthroughs of the century in terms of numbers of lives affected, providing a less expensive and more accessible means of treatment than intravenous rehydration (65). Promoted by WHO since 1978, oral rehydration is now theoretically accessible to about 60 percent of the children in developing countries, but is actually used to treat about 30 percent of the children who contract diarrhea. According to UNICEF, this treatment saves an estimated 1 million young lives a year (66) (67).
Because it is important for children to continue to receive nutrients during diarrheal episodes, oral rehydration therapy is increasingly considered to involve both the administration of fluids and continued feeding. Ongoing research suggests that cereal- based oral rehydration therapy, although still somewhat controversial, may have the potential to be more effective than the standard ORS solution, which prevents dehydration, but does not actually prevent diarrhea nor reduce its duration or amount. Cereal -based therapy can reduce fluid losses by 30-50 percent as well as shorten the duration of diarrheal episodes (68).
Even more important than treatment of diarrhea, however, is its prevention. Most diarrhea is caused by bacterial, viral, and parasitic infestations transmitted through water, food, and contact with fecal matter. Preventing diarrhea requires better sanitat ion and more abundant, cleaner water supplies, as well as health education aimed at promoting breastfeeding, immunization, improved personal hygiene and food handling practices, and the penning of farm animals such as chickens and cattle ( 69) (70). Exclusive breastfeeding in the first six months of a child's life, for example, can dramatically reduce the incidence of diarrhea; the addition of even water or tea to the infant's diet has been found to dou ble or sometimes triple the likelihood of diarrhea (71).
Vaccine-Preventable Diseases
At the end of the 1970s, the international community made a major commitment to immunizing the world's children against six major childhood diseases---measles, diphtheria, pertussis, tetanus, polio, and tuberculosis. This commitment has produced one of th e most spectacular public health successes of the past decade. Today, average immunization levels of children in developing countries are at least 80 percent for all vaccine-preventable diseases except measles (78 percent) and neonatal tetanus (which requ ires the immunization of women, only 38 percent of whom were immunized by 1990) (72). The United Nations Children's Fund (UNICEF) estimates that these successes are preventing at least 2.5 million child deaths each year. All tol d, more than 12 million lives have been saved and more than 1.5 million cases of polio prevented (73).
Despite this progress, more than 2.1 million children died of vaccine-preventable diseases in 1990 (74). Expanding immunization coverage further will be more difficult, because those not yet reached tend to be from the poorest f amilies, among whom disease and malnutrition are both more common and more likely to be fatal. The international community has committed itself to achieving 90 percent coverage by the year 2000, with a particular emphasis on reducing measles deaths by 95 percent and on eliminating tetanus and polio entirely (75)
Measles and neonatal tetanus are the biggest killers among vaccine-preventable diseases and also those for which immunization lags furthest behind. Measles accounts for some 900,000 deaths a year (76); it also causes malnutritio n, further illness, and loss of vitamin A. The incidence of illness and death in the period after a measles outbreak can be 10 times greater among children who had the disease than among those who did not (77). Immunization agai nst measles can have a significant effect on child mortality, helping to reduce deaths from all causes. In Bangladesh, for example, children who were vaccinated against measles experienced at least 40 percent lower mortality than those who were not (78).
Neonatal tetanus could be eliminated if all pregnant women were immunized and delivered their babies under hygienic conditions. Tetanus currently kills some 560,000 newborns each year and an estimated 15,000-30,000 mothers; it is an excellent barometer of the health status and well-being of mothers and newborns (79) (80) (81).
The eradication of smallpox through immunization in the 1970s provides a telling example of both the possibility and the cost-effectiveness of such efforts---approximately $1 billion a year is saved in vaccine and surveillance costs (82 ). Another success story is the near-total eradication of polio from the Americas. In 1985, bilateral, multilateral, and private voluntary agencies joined with the Pan American Health Organization in an intensive campaign to rid the hemisphere of polio. The campaign involved high immunization levels, enhanced surveillance to document and investigate each case, and measures to stop transmission whenever a new case occurred. In 1990, there were 18 new cases, compare d with 1,050 in 1986; as of July 1991, there were only 3 confirmed cases for the year. Complete eradication is anticipated in the near future (83).
Malaria
Approximately 40 percent of the world's population is at risk of malaria, which occurs in more than 100 countries (84). It is most endemic in sub-Saharan Africa, where often more than 50 percent of the population in rural areas is infected (85). Because of widespread underreporting, the exact number of deaths due to malaria is unknown but is estimated to be about 1 million annually (86), mostly in sub-Saharan Africa and mostl y in the younger age groups (an estimated 800,000 children under 5 die from malaria each year) (87). Those children who survive may acquire immunity against the most severe manifestations of the infection, but often the remnants of the disease adversely affect their growth, physical fitness, and educational achievement (88).
Environmental conditions contributing to the spread of malaria include stagnant waters around homes and construction sites; irrigation projects; industrial, hydroelectric projects requiring impoundment of water; changes in ecosystems caused by widespread deforestation, soil erosion, and flooding; overcrowding and unsanitary living conditions. Overuse of pesticides increases the mosquito's resistance and further aggravates the problem.
Combatting the disease requires controlling the mosquito population through appropriate use of chemical or biological means, preventing mortality through case management, and implementing a range of environmental management techniques depending on the pre dominant vector species. Malaria is transmitted through a complex of technical, political, social, cultural, environmental, and economic factors; to be successful, measures to reduce malaria mortality must be locally and regionally specific. Simple admini stration of even a very effective drug such as chloroquinine is not enough to combat the disease; when used in the absence of an effective primary health care system, chloroquinine has in fact contributed to the resurgence of malaria by increasing parasit e resistance. (See World Resources 1990-91, p. 58.) Nevertheless, when used in combination with strategies appropriate to local conditions, the drug can still provide a clinical cure in large areas of the world (89).
A ministerial level meeting to review the global malaria situation and develop new strategies is scheduled for October 1992 in Amsterdam. Organized by the World Health Organization, the meeting is to be preceded by a series of regional meetings in Africa, Asia, and Latin America.
Malnutrition
Although data are incomplete, a 1990 UNICEF survey suggests that more than one third of the developing world's children under 5 years of age (excluding China) are malnourished (90). Of these 150 million children, at least one in six---25 million---is severely malnourished. Most of the world's malnourished children reside in Asia--60 percent (91) excluding China, 80 percent including China (92). In sub-Saharan Africa, the inci dence of malnutrition appears to be increasing (93).
How frequently malnutrition is an immediate cause of death is unknown (94). UNICEF, however, estimates that it is a contributing cause in approximately one third of child deaths (95). In Latin America, malnutrition was found to be the underlying or related cause in more than half of all childhood deaths (96).
Malnutrition shows up quickly in young children, acting as an early warning sign of distress, ill health, and famine. The appearance of malnutrition in young children is believed to reflect the health and nutritional situation of all members of the popula tion (97).
Malnutrition can lower a child's immunity, making the child more susceptible to diseases such as diarrhea, measles, and respiratory infections. These in turn reduce appetite, cause nutrient loss, inhibit absorption, and alter the body's metabolism, thereb y resulting in inadequate dietary intake and further malnutrition. This vicious cycle of malnutrition and infection has been termed the "most prevalent public health problem in the world today" (98).
Often the cycle begins even earlier when malnourished women give birth to babies with low birth weight (2,500 grams or less). Some 350 million women are estimated to have nutritional anemia (99). These women are more likely to d ie in childbirth as well as to have babies too small to thrive. Between 12 and 15 percent of all babies in developing countries are born with low birth weight and these babies account for 30-40 percent of all infant deaths (100 ). Low birth weight babies are seven times more likely than other babies to die of respiratory infections and three times more likely to die of diarrhea (101). In the 1980s, nearly 1 of every 10 babies in Latin America had low birth weight which was a factor in 78 percent of early neonatal deaths (i.e., those deaths that occur in the first week of life) (102). Measures to reduce low birth weight---such as improved nutritional health for women and gir ls, more food and rest during pregnancy, and increased spacing between births---could significantly reduce infant deaths.
The international community has committed itself to halving the incidence of severe and moderate malnutrition among children by the year 2000. If that target is to be met, parents and community health workers must be given basic nutrition information and trained to monitor children's growth. For example, exclusive breastfeeding for the first few months of life can improve child health significantly. As noted above, it reduces diarrheal morbidity and provides newborns with the best possible nourishment as well as antibodies against common infections. UNICEF estimates breastfeeding could save 1.5 million lives a year. Because breastfeeding acts as a natural contraceptive by inhibiting ovulation, it lowers fertility rates and helps lengthen birth spacing, th us improving the health of both mother and child (103).
Two other widespread nutritional problems--vitamin A and iodine deficiency---require attention. Some 40 million children under 5 suffer from vitamin A deficiency (104). Every year, 250,000 children are permanently blinded by th e disease and another 25O,000 have their eyesight partially impaired. At least 100,000 of these die within a few weeks of contracting the disease (105). In addition, lack of vitamin A has been associated with other diseases, in cluding diarrhea and respiratory infection (106) (107). Vitamin A supplementation has been found to reduce measles-associated mortality by up to 50 percent (108) (109).
Improvements in vitamin A status, either through supplementation or dietary changes, are expected to save the sight of 250,000-500,000 children in developing countries each year, and the lives of 1 million children annually (110). In the longer term, adding foods rich in vitamin A such as green leafy vegetables and yellow fruits to diets is the best means of overcoming vitamin A deficiency (111). In fact, it has been argued that supplementation is a diversion of resources from the necessary task of improving diets (112). However, the mounting evidence on the benefits of adequate vitamin A consumption, combined with the difficulties in bringing about dietary changes and the seasonal or general lack of foods rich in vitamin A in many areas, is providing growing support for vitamin A supplementation for children and mothers to alleviate short-term or particularly severe deficiencies (113) (114) (115).
As a result of iodine deficiency disorder (IDD), 200-300 million people are afflicted with goiter, 20 million with mental retardation, and at least 6 million with cretinism. IDD is most prevalent in mountainous regions and flood-prone areas; when iodine i s washed from the soil, whole communities may suffer, with children the most affected. Without iodine, they grow up stunted, retarded, apathetic, and incapable of normal development, speech, or hearing. Ensuring that diets include iodized salt or administ ering iodine in oil either orally or through injection can remedy the deficiency (116).
There is no direct measure of a population's general health, well-being, and productive potential. Although mortality figures measure only the extreme outcome of ill-health--death---they also indicate the extent of health problems in a population. Obvious ly, widespread health problems can affect a country's productivity and development potential.
Both infant and under-five mortality rates are considered to reflect levels of nutrition (especially among pregnant women, infants, and children), education (especially female literacy) (117), general socioeconomic status, and access to health services (118). Of the two measures, the under-five mortality rate is considered a better technical indicator, both because data collection is better and because it is one of the few social indicators for which long-run time series are available.
Reducing child mortality is possible at various levels of national income. It can be achieved through broad social and economic development or through direct targeted interventions---interventions that for a number of reasons are also direct investments i n sustainable development.
First, as previously discussed, over the long run, reducing child deaths slows down the rate of population growth. In most countries, this change from high mortality-high fertility to low mortality-low fertility is not evident until under-five mortality r ates fall to 150---or even 100---deaths per 1,000 live births. From initial child mortality rates of 300 or more, many countries now have reached this critical point where further declines in child mortality can be expected to be accompanied by steep decl ines in fertility. Where strong family planning programs exist, the decline in births is likely to take place even more quickly (119). Figure 6.6 shows a strong association between lower child death r ates and the use of contraceptive measures in 67 countries for which data on both indicators are available.
Second, the environmental conditions that are both a symptom and a result of underdevelopment cause much of the ill health and disease affecting today's children. Measures that simultaneously address the related issues of poverty, ill health, and environm ental degradation include providing adequate water supplies, safe sanitation facilities, and small-scale irrigation (which can increase household food supply and income as well as avoid the negative environmental and health effects of large-scale irrigati on).
Third, healthy children who grow into healthy adults are more likely to make productive contributions to their communities and their countries, as well as to pass on positive health practices to the next generation. Sustainable development depends on a pr oductive, healthy, educated population. (See Chapter 1, "Dimensions of Sustainable Development.")
Health and Poverty
A society's overall level of income is not necessarily a good indicator of its children's life chances as measured by infant and child mortality rates. Compare, for example, Sri Lanka and Brazil. At an average annual per capita income of only $430, Sri La nka has one of the lowest child mortality rates of all developing countries (36 per 1,000). Brazil, with an average annual per capita income five times higher than Sri Lanka's ($2,550), has a child mortality rate twice as large (77 per 1,000). (See Chapte r 15, "Basic Economic Indicators," Table 15.1, and Chapter 16, "Population and Human Development," Table 16.3.) With an average annual per capita income of $182, the state of Kerala in India is poorer than India as a whole; yet in 1986, the state had an i nfant mortality rate of 27 per 1,000, while India's was 86 per 1,000 (120).
As the Human Development Report points out, social programs aimed at improving literacy and health care can have a bigger effect on child mortality than simply increasing GNP. Figures 6.6 and 6.7 show that child mortality is inversely correlated with the use of contraception and with female literacy. There is only a small correlation between GNP and child mortality within developing countries (121). However, in the ab sence of concentrated health and education programs, poorer children do suffer more health problems than wealthier children. In the poorer Northeast of Brazil, for example, the 1986 infant mortality rate of 116 per 1,000 live births is comparable to many African countries and more than twice that in the rest of Brazil (52 per 1,000) (122). After Sri Lanka changed its food subsidy policies in the late 1970s, the infant mortality rate in 1980 was twice as high among the poorest a gricultural workers (100 per 1,000) as it was for the country as a whole (50 per 1,000) (123).
In developed countries as well, it is the poorest segments of society whose children suffer most. In the United States, the Department of Health and Human Services has found that poor children are more likely both to be ill and to have many more risk fact ors for poor health than children in families with higher incomes. One quarter of all children under age 6 are members of families living below the government-defined poverty level. These children are more likely to suffer from prematurity, low birth weig ht, birth defects, and infant death. They are twice as likely, between the ages of 1 and 2, to have iron deficiency anemia. They are also at greater risk of growth retardation and impaired mental and physical development, and they experience more sickness from infectious and other debilitating conditions. In 1980, U.S. children from families with incomes under $5,000 had slightly more than nine disability days, compared with four disability days for children from families with incomes of $25,000 or more ( 124).
In the United Kingdom, a child born to professional parents can expect to live more than five years longer than a child born to parents who perform unskilled manual labor (125). In the Soviet Union, infant mortality rates in 19 87 were 19 per 1,000 live births in urban areas and 27 per 1,000 live births in rural areas (126). Such large gaps can be found even within communities. In Guatemala City, 1976 data showed that the mortality rate for children u nder age 2 was 113 per 1,000 live births for poor illiterate women, compared with 33 per 1,000 live births for middle-class women with secondary education (127).
Water and Sanitation
Universal access to safe drinking water and to sanitary disposal of excreta are two of the major international targets for improving the health and well-being of children. These goals were set during the International Drinking Water Supply and Sanitation Decade of the 1980s and endorsed again at the 1990 World Summit for Children. As of 1990, 81 percent of urban areas and 58 percent of rural areas had access to safe water supplies; 71 percent of urban areas and 48 percent of rural areas had access to sani tation (128).
A 1990 review of 144 community-level studies concluded that when water and sanitation are made available to people, substantial health impacts can be achieved. In particular, the review found that water and sanitation was associated with a median reductio n in child mortality of 55 percent. These community studies also suggest that, particularly for diarrheal disease, improvements in excreta disposal and water quantity have even greater health impacts than improvements in water quality (129).
The gains to be made from improving water supplies (both quantity and quality) and sanitation are not automatic, however. Simply installing water taps, pit latrines, hand pumps, and other hardware is not enough; their success depends as well on community participation and changes in behavior (130). Studies have found, for example, that handwashing can reduce the incidence of diarrheal disease by 14-48 percent (131).
The cumulative effect of reducing a number of water and sanitation-related diseases may be significantly greater than the measurement of any one disease would indicate; child mortality, for example, may be reduced more than the incidence of diarrhea (132). Moreover, improvements in water and sanitation may reduce the severity of disease even more than the incidence.
There are also indirect benefits that follow initial improvements. Difficult to quantify, these benefits are nonetheless significant. Well-designed investments in water and sanitation bring socioeconomic, educational, and nutritional benefits. Additionall y, by reducing illness they improve productivity and the ability to learn, which in turn increase general well-being, making water and sanitation measures even more cost-effective (133).
The Role of Women
An estimated three quarters of all health care takes place at home, where women---particularly in their role as mothers---generally have responsibility for promoting their families' health and nutrition (134). Much has been lea rned recently about which factors help or hinder women in improving their children's health.
Women's education is closely related to child health, whether health is measured in terms of infant and child mortality or children's nutritional status (135) (136). Figure 6.7 shows a high correlation between female literacy and child mortality rates. Detailed studies of 28 countries show a nearly consistent inverse relationship between child mortality and mothers' education (137).
Women's education can improve children's health through a variety of mechanisms: increased use of health services and better knowledge of nutrition; more decisionmaking power within the family and the community; and greater earning power. Women with highe r levels of education are more likely to plan their families and thus to increase birth spacing, reducing a major mortality risk factor (138).
Increased education of mothers often is associated with higher education levels of fathers, higher levels of household income, the availability of water and sanitation, and the availability of other health inputs---all factors that also tend to be associa ted with improved child health. The net effect of either mother's or father's education on health is difficult to determine precisely (139) (140). Education of a mother is estimated to be twice as ef fective as education of a father in lowering infant and child mortality (141). It is not necessarily the content of the education that makes a difference in children's health but the mother's increased access to information, in cluding health information (142).
Lack of education is not the only problem constraining mothers from protecting their children's health. Poor rural women in developing countries often work 60 to 90 hours per week gathering wood, collecting water, growing and cooking food, contributing to the family income, and caring for their children (143). For these women, steps to make immunization more accessible and the administration of oral rehydration therapy easier may be key to their ability to raise healthy childre n (144).
Health Care
The technologies---such as immunization and oral rehydration therapy---that have made a significant difference in child health depend on a well-informed parent supported by an accessible health worker. The parent, usually the mother, must recognize the in itial symptoms in time to provide home care or seek outside assistance. She must also be able to turn to someone who can immunize children, take other steps to prevent illness, and treat children who do fall ill. This person need not be an expensively edu cated physician; a well-trained health worker, preferably one with roots in the community and opportunities for both further education and support, can handle most situations. Access to such community health workers is essential if the opportunities for s ignificantly reducing child deaths are to be realized.
Almost three quarters of the health expenditures of developing countries are devoted to urban hospitals that provide expensive, Western-style curative care to a minority of the population. UNICEF estimates that reducing this amount to 45 or 50 percent of total government expenditures on health would release enough funds to train the 1 million health workers needed to provide health services to the poorest 1 billion people in the developing world (145).
Although most environmental causes of poor health in developing-country children are related to poverty and a lack of modern development---lack of water and sanitation, poor housing, indoor air pollution resulting from the burning of wood and dung---some parts of the developing world face health hazards from industrial pollutants and urban development. Aggregate data are scarce, but evidence is mounting that industrialization and urbanization are combining to expose some populations to a variety of toxic chemicals contaminating the air, water, soil, and food. It is an area in which the need for more research and better data gathering is urgent.
Industrial Pollutants
Pollution in whatever form affects children more than adults, and poor children---who are exposed to more kinds and higher levels of pollution---are affected most of all. Children's smaller body weights and developing organs put them at greater risk. So d o their habits: infants suck indiscriminately on contaminated objects; older children play on streets filled with car fumes and lead exhaust, on sewage-polluted beaches, or on open spaces that collect hazardous wastes. Malnourished and disease-prone child ren are even more vulnerable (146).
The fetus is perhaps most vulnerable. Methyl mercury, pesticides, polychlorinated byphenyls (PCBs), carbon monoxide, and such self-administered contaminants as alcohol and tobacco have been shown to have adverse health consequences for exposed fetuses (147). Although no aggregate data exist on the extent of the problem, selected data provide a good indication.
Mercury in seafood ingested by pregnant women has been linked to cerebral palsy in infants. On average, mercury levels in these babies' blood is 47 percent higher than those of their mothers (148). Children whose mothers ate fo ods contaminated with PCBs have suffered various forms of retarded growth (149). Carbon monoxide, which WHO has found regularly reaches unhealthy levels in many cities, can result in decreases in fetal weight, increases in peri natal mortality, and brain damage, depending on the length of time a pregnant woman was exposed and the concentration in the air. Here, too, the concentration in the fetus generally exceeds that in the mother (150).
Air Pollution
Air pollution---once a problem only in the industrialized world---now affects most large urban centers in developing countries; the number of vehicles, poor vehicle maintenance, industrial growth, the absence of effective air-quality regulations, and the burning of charcoal, wood, and paraffin by growing slum populations for fuel and cooking combine to create some of the dirtiest cities in the world (151) (152). Although environmental improvements th ere have been remarkable in recent years, the city of Cubatao, Brazil in 1980 reported grim statistics regarding health effects of air pollution. In the industrial city, 40 out of every 1,000 babies were stillborn; another 40, mostly deformed, died in the first week of life. In the same year, with a population of 80,000, Cubatao had some 10,000 medical emergencies involving tuberculosis, pneumonia, bronchitis, emphysema, asthma, and other nose and throat ailments (153). The lin k between air pollution and the incidence of respiratory and pulmonary diseases in children, who inhale about twice as many pollutants per unit of body weight as do adults, is well-demonstrated (154) (155).
Lead Poisoning
Lead is a particular problem for children under 6. Excessive exposure impairs intelligence, growth, ability to hear and perceive language, and concentration (156). Even exposure to low levels seems to be associated with subsequ ent intellectual deficiencies (157) (158). The level of what is considered toxic has been continually reduced in the last 10 to 15 years as a result of new research showing how severe the consequence s of lead exposure can be (159) (160).
Lead-based paint and exhaust fumes from leaded gasoline are two major sources of lead exposure; however, some children may be dangerously exposed from other sources as well. Lead workers bring home lead dust on their clothes, shoes, and hair (161). Painting, pottery glazing, jewelry making, stained glass work, metal sculpting, and other cottage craft industries that use lead or products that contain lead may involve the whole family; in Mexico, children whose families manufactu red pottery were found to have higher blood-level concentrations and lower mental performance than children from families of similar socioeconomic background but who were employed in other occupations (162).
While airborne lead concentrations from industrial emissions and automobile exhaust are declining in most industrialized countries, they are increasing in developing-country urban areas (163). High levels of airborne lead have been found along busy roads in Delhi, Kuala Lumpur, and Zimbabwe (164) (165) (166). A survey of children living near a lead-smelting plant in Brazil found high levels of b oth zinc protoporphyrin and lead in their blood; the levels correlated to the children's age, their proximity to the plant, and length of residence (167). In Mexico City, 7 out of 10 newborns were found to have lead blood level s higher than the WHO norm (168).
Even in the United States, where the lead content of paint used for residential structures, toys, furniture, and eating utensils has been limited since 1971 (169) and unleaded gasoline has been required for new automobiles sinc e 1975, 3-4 million children are estimated to have lead blood levels above the maximum threshold defined by the Environmental Protection Agency for neuropsychological impairment. Approximately 17 percent of all children living in metropolitan areas have b lood levels in this range; among poor black children, the rate is 62 percent (170).
Water Pollution
In many developing countries, urban water sources used for drinking, washing, and cooking are threatened by biological pollution from human waste and chemical pollution from industrial toxic wastes. South America, for example, pollutes nearly 11 times mor e freshwater per capita than Europe, largely because less than 10 percent of its sewage is treated (171).
Infants, who need more fluids in relation to body weight than older children and adults, are particularly vulnerable to health hazards caused by water pollution. Nitrate in groundwater is a growing cause of concern in several countries, as the use of nitr ate fertilizer and manure increases. Not in itself dangerous, nitrate combines with bacteria in the mouth to become nitrite, which can induce methemoglobinemia (a reduction in the oxygen-carrying capacity of the blood), especially in infants who drink bab y formula mixed with water containing nitrates (172).
Hazards of Urbanization
Although urban areas have lower infant and child mortality rates in the aggregate than rural areas, the health status of urban subpopulations varies widely. The poorest urban populations---often living in illegal squatter settlements---suffer from overcro wding, inadequate housing, contaminated water supplies, poor or nonexistent waste disposal and sanitation, and exposure to industrial pollutants. Large cities tend to have the highest concentrations of water, sanitation, and health care facilities, but as many as 30-60 percent of the poorest people do not have access to them (173).
Numerous studies show that children living in these conditions have higher rates of diarrhea, respiratory infection, tuberculosis, malnutrition, and death than children in other urban communities or even in surrounding rural areas (174 ). Children in squatter settlements may be 50 times as likely to die before age 5 than those born in developed countries (175).
In addition, the conditions of their poverty put these urban children at increased risk of accidents, crimes, violence, and psychological harm. A growing number of children live in the streets--without shelter, adult supervision, or income.
Dramatic declines in infant mortality took place in the industrialized countries in the early 20th Century, not primarily as a result of advances in medicine, but as a direct result of advances in overall living conditions, including better nutrition, imp roved hygiene and sanitation, and voluntary birth limitation (176). The question today is whether further mortality decreases must wait for overall economic development or whether they can be achieved even in advance of overall improvements in the economy---by pursuing concerted strategies to improve food supply, water and sanitation, education, and health care.
For the last 10 years, WHO, UNICEF, and other multilateral agencies have urged the international community to pursue an aggressive "child survival" strategy. The program has focused on promoting wide-spread acceptance of several "technologies"---including oral rehydration therapy, breastfeeding, improved weaning practices, and immunization---and on providing increased access to food, family planning, and female literacy.
The strategy has had some outstanding successes. UNICEF in 1991 calculated that child survival interventions were saving 3.2 million young lives each year (177). But high mortality rates still prevail in many countries, and gro wing problems such as pediatric HIV and AIDS threaten the gains that have been made.
In the 10 countries of Central and East Africa, for example, HIV/AIDS could cause 250,000 to 500.000 additional deaths a year among children under age 5 by the year 2000. These children will be extremely sick before they die, putting severe strains on hea lth care resources. Additionally, by the year 2000, HIV/AIDS is expected to orphan as many as 5.5 million children---11 percent of all the region's children under age 15 (178).
The World Summit for Children brought together representatives from 159 countries, including 71 heads of state or government. In a Declaration on the Survival, Protection and Development of Children, these representatives made a commitment to reduce child death rates by one third and malnutrition rates by one half by the end of the decade. The accompanying Plan of Action for meeting those goals contains detailed targets for specific diseases, nutrition, immunization, family planning, breastfeeding, water and sanitation, and education. (See Box 6.2.)
The world summit epitomized the growing global consensus that a commitment to children is important both in itself and as an investment in the sustainability of the planet. In November 1989, the United Nations adopted the Convention on the Rights of the C hild, which sets standards for children's survival, health, and education and seeks to protect children who are exploited, abandoned, or abused. As of August 1991, 95 countries had ratified the Convention; another 45 had signed (but not yet ratified) it ( 179).
Meeting the goals set at the world summit will cost approximately $20 billion a year, according to UNICEF estimates, and will require commitments from both developing and developed countries (180). Developing countries will hav e to reallocate some military spending to social spending and divert some funding from hospitals and secondary education to primary health care and primary education. Additional support from industrialized countries will also be necessary to achieve these goals.
The status and progress of children's health and nutrition is a telling measure of society's overall development. Children must not only survive but be given the opportunity to thrive.
Conditions and Trends was written by World Resources Senior Editor Robert Livernash. Focus On Children's Health was written by Rosemarie Philips, a writer and editor on environment and development issues in Alexandria, Virginia. Dirk Bryant, World Re sources research assistant, contributed to this chapter.
32. Pan American Health Organization (PAHO), "Update The Cholera Situation in the Americas," Epidemiological Bulletin. Vol. 12, No. 3 (PAHO, Washington, D.C., 1991), Table 1, p. 11.
34. Renate Plaut, Epidemiologist, Health Situation and Trend Assessment Program, Pan American Health Organization, Washington, D.C., September 1991 (personal communication).
53. Pan American Health Organization (PAHO), Health Conditions in the Americas, Vol. I, Scientific Publication No. 524 (PAHO, Washington, D.C., 1990), p. 404.
65. "Water with Sugar and Salt," The Lancet (August 5, 1978), p. 300.
73. Op. cit. 58, pp. 1, 5, and 15.
83. Roxane M. Eikhof, Information Officer, Expanded Program on Immunization, Pan American Health Organization, Washington, D.C., September 1991 (personal communication).
96. R.R. Puffer and C. Serrano, Patterns of Mortality in Childhood, Scientific Publication No. 262, Pan American Health Organization (PAHO), Washington, D.C., 1973, cited in Health Conditions in the Americas: 1990 Edition , Vol. 1, Scientific Publication No. 524 (PAHO, Washington, D.C., 1990), Note 17. p. 116.
121. Dirk Bryant, Research Assistant, World Resources Institute, unpublished data, 1991.
127. H. Behm and E. Vargas, Guatemala: Diferencias Socieoconomicas de la Mortalidad de los Menores de dos Anos 1968-1976 (Ministry of Economics, Directorate General of Statistics, Republic of Guatemala and CELADE, San Jose, Costa Rica. 1984), Senes A/1044 , cited in Pan American Health Organization (PAHO), Health Conditions in the Americas: 1990 Edition Vol. I, Scientific Publication No. 524 (PAHO, Washington, D.C., 1990), p. 47.
140. Op. cit. 135, pp. 213-214.
143. United Nations (U.N.), The World's Women: 1970-1990) U.N., New York, 1991), p.82.
167. Fernando M. Carvalho, Annibal M. Silvany-Neto, Tania M. Tavares, et al., "Lead Poisoning Among Children From Santa Amaro, Brazil," Bulletin of the Pan American Health Organization (PAHO), Vol. 19, No. 2 (PAHO, Washin gton, D.C., 1985), p. 168.
