In the United States, in 2001, life expectancy at birth reached a record high of 77.2 years for all sex and race groups combined. However, the infant mortality rate was slightly higher than in previous years, and mortality for black infants was 2.5 times that for white infants. A large proportion of childhood deaths continue to occur as a result of preventable injuries. [The slightly higher infant mortality is due to an increase in multiple births derived in part from new technologies that help women conceive (Table 2.1).]

Many adult-onset diseases have their origins in childhood. Perhaps no better example exists than obesity, with its many medical complications. Type II diabetes (once a rarity in
children) is directly related to obesity, and it accounts for 8% to 45% of all new cases of diabetes in childhood. It is significant that the time required from recognition of the disease to development of complications is no different in children and adults. Increases in television watching and fast-food consumption, combined with more sedentary endeavors such as computer games, all play major roles in childhood obesity. Early childhood obesity is associated with more severe obesity among adults. Other data suggest that overweight and obese school-aged children are more likely to be the victims and perpetrators of bullying behavior than their normal-weight peers.

As pediatrics enters the new millennium, it is appropriate to assess the changes in the demographics of the pediatric population that have taken place. The twentieth century saw a significant growth (approximately 165 million people) in the U.S. population. In 1900, 40.5% of the total U.S. population was under 18 years of age. Over the next several decades, this percentage continued to decline to a low of 30.6% in 1940. Not unexpectedly, the decades following World War II saw an increase in the percent of the population that was under age 18. The increase continued until the 1980 U.S. census, which again demonstrated a decline in the percentage of the total U.S. population under 18 years of age. This decline continued until the close of the century. According to the 2000 census, 25.7% of the U.S. population was under the age of 18. To some extent, this decline in the percentage of the younger population is a result of the increased longevity of the population overall. During these same time periods, an increase occurred in the percent of the population over 65 years of age.

It is important to note, however, that during a century that saw a decline in infants, children, and adolescents under the age of 18 as a percentage of the population, the actual numbers of individuals in these age groups increased from 30.7 million in 1900 to approximately 72.3 million in 2000. This number is expected to reach 80.3 million in 2020. For the proper allocation of resources and the development of health policy, it is important to make an accurate determination of the percentage of the population under 18 years of age as a part of the total U.S. population. However, the actual number of people in this age group has significant implications for those who provide pediatric health care. Pediatricians of the future will be faced with responsibility for the health care of an increasing absolute number of children at a time when those children represent a smaller fraction of the total population.

Several demographic changes and other related factors have implications for the pediatrician workforce and the pediatric population. The most compelling of these demographic changes are those pertaining to race and ethnicity. The percentage of children who are white and non-Hispanic decreased from 74% in 1980 to 64% in 2000. During the same 20-year period, the percentages of black, Hispanic, and Native American/Alaska Native children have been fairly stable. The percentage of Asian/Pacific Islander children doubled from 2% to 4% of all U.S. children between 1980 and 2000. This percentage is projected to continue to increase to 6% in 2020, although the absolute numbers remain low.

The number of Hispanic children has increased faster than that of any other racial and ethnic group, growing from 9% of the child population in 1980 to 16% in 2000. By 2020, it is projected that more than 1 in 5 children in the United States will be of Hispanic origin. From the 2000 U.S. census, respondents who reported more than one race were more likely
to be under age 18 than those who identified only one racial origin. Of the 6.8 million people in the two or more race category, 42% were under age 18. This contrasts with one-race category, in which 25% of these 274.6 million people were under 18 years. In 1979, 1.3 million children spoke their native language at home and had difficulty speaking English. By 1999, it is estimated that this number had doubled. In addition to race and ethnicity, other types of diversity within the pediatric population also will have implications for the allocation of resources as well as access to and utilization of pediatric health care services. These influences include religious diversity, sexual orientation, socioeconomic status, gender, and a host of other attributes.