Across the globe, there are significant variations in infant mortality rates by nation, by region, by economic status, and by level of industrial development, the categorizations employed by the World Bank and the United Nations (Table 1-1). Most of the decline in infant mortality in the USA and other industrialized countries since 1970 is attributable to a decrease in the birthweight-specific infant mortality rate related to neonatal intensive care, not to the prevention of low-birthweight births (Chapter 87). The majority of deaths of infants younger than 1 yr of age occur in the 1st 28 days of life, most of these in the 1st 7 days; moreover, a large proportion of the deaths in the 1st 7 days occur on the 1st day. An increasing number of severely ill infants born at very low birthweight survive the neonatal period, however, and die later in infancy of neonatal disease, its sequelae, or its complications (Tables 1-2 through 1-4).

Table 1-1 CHILD HEALTH INDICATORS WORLDWIDE BY REGION

Table 1-2 DEATH RATES FOR ALL CAUSES, BY SEX, RACE, AND AGE: UNITED STATES, SELECTED YEARS 1960 AND 2005

Table 1-3 DEATHS RATES FOR ALL CAUSES AMONG CHILDREN AND YOUNG ADULTS ACCORDING TO SEX, RACE, HISPANIC ORIGIN, AND AGE: 2006

Table 1-4 INFANT, NEONATAL, AND POSTNATAL DEATHS AND MORTALITY RATES BY SPECIFIED RACE OR ORIGIN OF MOTHER: USA, 2005

Causes of death vary by developmental status of the nation. In the USA, the 3 leading causes of death among infants were congenital anomalies, disorders related to gestation and low birthweight, and sudden infant death (Table 1-5). By contrast, in developing countries, the majority of infant deaths result from infectious diseases; even in the neonatal period, 24% of deaths are caused by severe infections and 7% by tetanus. In developing countries, 29% of neonatal deaths are due to birth asphyxia and 24% due to complications of prematurity.

Table 1-5 LEADING CAUSES OF DEATH AND NUMBERS OF DEATHS, ACCORDING TO AGE: UNITED STATES 2005

In the majority of countries, the most robust predictor of infant mortality is a poor level of maternal education (and therefore another of the MDG addresses the need for universal access to primary schooling for girls). Other maternal risk characteristics, such as unmarried status, adolescence, and high parity, correlate with increased risk of postneonatal mortality and morbidity and low birthweight.

Health Among Postinfancy Children

A profound improvement in child health within industrialized nations occurred in the 20th century with the introduction of antibacterial disinfectants, antibiotic agents, and vaccines. Efforts to control infectious diseases were complemented by better understanding of nutrition. In the USA, Canada, and parts of Europe, new and continuing discoveries in these areas led to establishment of public well child clinics for low-income families. Although the timing of control of infectious disease was uneven around the globe, this focus on control was accompanied by significant decreases in morbidity and mortality in all countries. The smallpox eradication program of the 1970s resulted in the global eradication of smallpox in 1977. The introduction in the 1970s of the Expanded Program of Immunizations (universal vaccination against polio, diphtheria, measles, tuberculosis, tetanus, and pertussis) by the World Health Organization (WHO) and United Nations Children’s Fund (UNICEF) has resulted in an estimated annual reduction of 1 to 2 million deaths per year globally. Recognizing the importance of prevention of infectious diseases to the health of children, several countries among the 50 currently ranked by the World Bank as among the poorest nations (per capita income <$750/yr) have invested heavily in infectious disease control through the development of internal vaccine production capability. As diarrheal diseases continued through the mid-1970s to account for ≈25% of infant and childhood deaths in the nonindustrialized countries (∼4 million deaths per year at that time), attention turned to the development and utilization of oral resuscitation fluids to sustain children through potentially life-threatening episodes of acute diarrheal diseases. Oral rehydration solutions are largely credited with the current reduction of diarrheal deaths annually to 1.5 million.

In the later 20th century, with improved control of infectious diseases (including the elimination of polio in the Western hemisphere) through both prevention and treatment, pediatric medicine in industrialized nations increasingly turned its attention to a broad spectrum of conditions. These included both potentially lethal conditions and temporarily or permanently handicapping conditions; among these disorders were leukemia, cystic fibrosis, diseases of the newborn infant, congenital heart disease, mental retardation, genetic defects, rheumatic diseases, renal diseases, and metabolic and endocrine disorders. Thus, in industrialized nations, the end of the 20th century and 1st decade of the 21st century have been marked by accelerated understanding of new approaches to the management of many disorders as a consequence of advances in molecular biology, genetics, and immunology.

Increasing attention has also been given to behavioral and social aspects of child health, ranging from re-examination of child-rearing practices to creation of major programs aimed at prevention and management of abuse and neglect of infants and children. Developmental psychologists, child psychiatrists, neuroscientists, sociologists, anthropologists, ethnologists, and others have brought us new insights into human potential, including new views of the importance of the environmental circumstances during pregnancy, surrounding birth, and in the early years of child rearing. The later 20th century witnessed the beginning of nearly universal acceptance by pediatric professional societies of attention to normal development, child rearing, and psychosocial disorders across the continents. In the last decade, irrespective of level of industrialization, nations have developed programs addressing not only causes of mortality and physical morbidity (such as infectious diseases and protein-calorie malnutrition), but also factors leading to decreased cognition and thwarted psychosocial development, including punitive child-rearing practices, child labor, undernutrition, war, and poor schooling. Obesity is recognized as a major health risk not only in industrialized nations, but increasingly in transitional countries. Progress at the turn of the 21st century in unraveling the human genome offers for the 1st time the realization that significant genetic screening, individualized pharmacotherapy, and genetic manipulation will be a part of routine pediatric treatment and prevention practices in the future. The prevention implications of the genome project give rise to the possibility of reducing costs for the care of illness but also increase concerns about privacy issues (Chapter 3).

Although local famines and disasters, and regional and national wars have periodically disrupted the general trend for global improvement in child health indices, it was not until the advent of the AIDS epidemic in the later 20th century that the 1st substantial global erosion of progress in child health outcomes occurred. This erosion has resulted in ever-widening gaps between childhood health indices in sub-Saharan Africa compared to the rest of the world. From 1990 to 2002, life expectancy in sub-Saharan Africa decreased from 50 yr to 46 yr; although, as of 2008, it had returned to 52 yrs. Increasing rates of tuberculosis and continued problems with pandemics such as cholera further challenge many of these nations. Strains of drug-resistant malaria are also a major concern in isolated areas around the world, but 90% of malarial deaths (the majority among children) are occurring in sub-Saharan Africa. Diseases once confined to limited geographic niches, including West Nile virus, and diseases previously uncommon among humans, such as the avian flu virus, increased awareness of the interconnectedness of health around the world. Formerly perceived as a problem of industrialized nations, motor vehicle crashes are now a major cause of mortality in developing countries as well.

Enormous disparities exist in childhood mortality rates across the globe (see Table 1-1). Among the ∼8.7 million childhood deaths occurring worldwide, ≈50% occur in sub-Saharan Africa, home to <10% of the world’s population. Fifty percent of the world’s childhood deaths are occurring in 6 nations; 90% of childhood deaths are occurring in only 42 of the world’s 192 nations. In 2008, the USA had an under-5 mortality rate of 8/1,000 live births. Forty-two nations had under-5 mortality rates lower than that of the USA, with Singapore, Finland, Luxembourg, Iceland, and Sweden having the lowest rates at 3/1,000. The comparable child mortality rate in sub-Saharan Africa was 144/1,000 live births. As of 2008, Afghanistan has the highest under-5 mortality rate of 257/1,000 live births, followed by Angola at 220/1,000 live births and Chad at 209/1,000 live births. In 1990 Afghanistan and Angola had an under-5 mortality rate of 260/1,000 live births, showing minimal improvement over 2 decades. Causes of under-5 mortality differ markedly between developed and developing nations. In developing countries, 66% of all deaths resulted from infectious and parasitic diseases. Among the 42 countries having 90% of childhood deaths, diarrheal disease accounted for 22% of deaths, pneumonia 21%, malaria 9%, AIDS 3%, and measles 1%. Neonatal causes contributed to 33%. The contribution for AIDS varies greatly by country, being responsible for a substantial proportion of deaths in some countries and negligible amounts in others. Likewise, there is substantial co-occurrence of infections; a child may die with HIV, malaria, measles, and pneumonia. Infectious diseases are still responsible for much of the mortality in developing countries. In the USA, pneumonia (and influenza) accounted for only 2% of under-5 deaths, with only negligible contributions from diarrhea and malaria. Unintentional injury is the most common cause of death among U.S. children ages 1-5 yr, accounting for about 33% of deaths, followed by congenital anomalies (11%), malignant neoplasms (8%), and homicides (7%). Other causes accounted for <5% of total mortality within this age group (see Table 1-5). Although unintentional injuries in developing countries are proportionately less important causes of mortality than in developed countries, their absolute rates and their contributions to morbidity are substantially greater.

Morbidities Among Children

It is important to examine morbidities as well as mortality. Adequately addressing special health care needs is important in all countries both to minimize loss of life and to maximize the potential of each individual.

In the USA, ≈70% of all pediatric hospital bed days are for chronic illnesses; 80% of pediatric health expenditures are for 20% of children. In 2006, about 13.9% of U.S. children were reported to have special health care needs; 21.8 percent of households with children had ≥1 child with a special health care need (Chapter 39). Significantly more poor children and minority children have special health care needs. Although there are multiple chronic conditions and the prevalence of these disorders vary by population, 2 of these morbidities—obesity and asthma—have a substantial and increasing presence worldwide and are associated with substantial health consequences and costs. In the USA, ∼25% of children and adolescents are overweight, representing a 2.3- to 3.3-fold increase over the past 25 yr. Similar rates have been reported from Australia and multiple countries in Europe, Egypt, Chile, Peru, and Mexico (Chapter 44).

Also increasing in prevalence among industrialized nations and in middle- and low-income nations with substantial urbanization are rates of asthma. In the mid-1990s, the USA reported an annual prevalence rate of wheezing of 57.8/1,000 among children ages 0-4 yr and 74.4/1,000 among youth ages 5-15 yr, approximately 2-fold higher than comparable prevalence rates in 1980. In 2007, the Centers for Disease Control and Prevention (CDC) estimated that 9% of U.S. children have asthma, including 19.2% of Puerto Rican and 12.7% of non-Hispanic black children. The International Study of Asthma and Allergies in Childhood has conducted a systematic review of asthma prevalence, with compelling evidence for a substantial global burden of childhood asthma, although rates vary substantially between and within countries. The highest annual prevalence rates are in the United Kingdom, Australia, New Zealand, and Ireland, with the lowest rates in Eastern European countries, Indonesia, China, Taiwan, India, and Ethiopia (Chapter 138).

Chronic cognitive morbidities represent another substantial problem. Although different diagnostic criteria have been applied, attention-deficit/hyperactivity disorder (ADHD) has been identified in 5-12% of children in countries across the globe. Rates exceeding 10% have been reported in the USA, New Zealand, Australia, Spain, Italy, Colombia, and Great Britain. Variations in cultural tolerance and/or differences in screening approaches or tools may account for some of the differences in prevalence of the disorder by country, but genetic and gene-environmental interactions may also play a role. Despite variations in rate, the condition is universal. Beyond the personal and familial stress caused by the disorder, costs to the educational system are considerable. It is estimated that in 2010 the U.S. drug treatment costs for ADHD will exceed $4 billion. In developing countries without resources for special education, these children are unlikely to fulfill their academic potential (Chapter 30).

Mental retardation affects ≈1-3% of children in the USA, with ∼80% of these children having mild retardation. Rates are severalfold higher among very low birthweight infants, although data from European cerebral palsy (CP) registries has revealed a significant decrease in the prevalence of CP in very low birthweight infants, from 60.6 per 1,000 live births in 1980 to 39.5 per 1,000 live births in 1996. In the USA, there is substantial variation in rates of mild retardation by socioeconomic status (9-fold higher in the lowest compared to the highest socioeconomic stratum) but relatively equivalent rates of severe retardation. A similar income-related distribution is found in other countries, including some of the most impoverished countries such as Bangladesh. Lower overall rates have been reported in some countries, including countries ranging from Saudi Arabia to Sweden to China; the difference is primarily in the prevalence of mild retardation (Chapter 33).

The prevalence of post-traumatic stress disorder (PTSD) varies considerably around the globe, but in children with substantial exposure to violence, the rates may be very high. After the attacks on the World Trade Center towers and the Pentagon in 2001, 33% of U.S. children had experienced 1 or more symptoms of PTSD. One half of Palestinian children experience at least 1 significant lifetime trauma and >33% (66% of those experiencing trauma) meet the criteria of PTSD. Natural disasters such as the tsunami of 2004 and the Haitian and Chilean earthquakes and Pakistani floods of 2010; war, including those in Afghanistan, Sudan, and Iraq; and urban violence all leave their indelible marks on the minds of children.

Special Risk Populations

In addition to the enormous differences in infant and child health between regions and nations, within countries there are substantial variations in morbidity and mortality rates by socioeconomic class and ethnicity. Most children at special risk need a nurturing environment but have had their futures compromised by actions or policies arising from their families, schools, communities, nations, or the international community. These problems have several causes, whether the end result is homeless children, runaway children, children in foster care, or children in other disadvantaged groups. The most effective preventive approach involves alleviation of poverty, inadequate parenting, discrimination, violence, poor housing, and poor education. Optimal care of these children requires reducing barriers to health care with organized programs, multidiscipline teams, and special financing.

Children in Poverty

Family income is central to the health and well-being of children. Children living in poor families, especially those located in poor communities, are much more likely than children living in upper- or middle-class families to experience material deprivation and poor health, die during childhood, score lower on standardized tests, be retained in a grade or drop out of school, have out-of-wedlock births, experience violent crime, end up as poor adults, and suffer other undesirable outcomes. In 2008, 20.7% of U.S. children <18 yr (21% of those less than 6 yr) lived in poverty (defined as income <$21,756/yr for a family of 4), a rate among the highest of developed countries. Seven percent lived in extreme poverty. The poverty rates are higher for children than adults and are highest for infants and toddlers. Children who are poor have higher than average rates of death and illness from almost all causes (exceptions being suicide and motor vehicle crashes, which are most common among white, non-poor children). Many factors associated with poverty are responsible for these illnesses; crowding, poor hygiene and health care, poor diet, environmental pollution, poor education, and stress.

Figure 1-2 Poor children across South-Eastern Asia are much more likely to die before age 5 than their wealthier peers.

(From World Health Organization: World health statistics 2007, Geneva, 2007, World Health Organization, p 74; and United Nations Development Programme: Human Development Report 2007/08: fighting climate change: human solidarity in a divided world, New York, 2007, United Nations Development Programme, p 255.)

Poverty and economic loss diminish the capacity of parents to be supportive, consistent, and involved with their children. Clinicians at all times but especially in the context of a national or global recession need to be especially alert to the development and behavior of children whose parents have lost their jobs or who live in permanent poverty. Fathers who become unemployed frequently develop psychosomatic symptoms, and their children often develop similar symptoms. Young children who grew up in the Great Depression in the USA and whose parents were subject to acute poverty suffered more than older children, especially if the older ones were able to take on responsibilities for helping the family economically. Such responsibilities during adolescence seem to give purpose and direction to an adolescent’s life. The younger children, faced with parental depression and unable to do anything to help, suffered a higher frequency of illness and a diminished capacity to lead productive lives even as adults.

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