5. The CDC Growth Chart Reference Population

Data Used to Create the Growth Charts

The racial and ethnic distribution in the reference population is representative of the U.S. population at the time each of the NHES and NHANES surveys were conducted.

Results of a CDC analysis of the 1980 census provide a reasonable basis for describing racial/ethnic representation in the growth reference. In 1980, 74 percent of U.S. children under 20 years of age were White, non-Hispanic; 14 percent were Black, non-Hispanic; 9 percent were Hispanic; 2 percent were Asian/Pacific Islander; and 1 percent were American Indian/Alaskan Native (Census Bureau, 1992).

CDC promotes one set of growth charts for all racial and ethnic groups. Racial- and ethnic-specific charts are not recommended because studies support the premise that differences in growth among various racial and ethnic groups are the result of environmental rather than genetic influences (Lusky, 2000; Mei, Yip, Trowbridge, 1998; Martorel, Mendoza, Castello, 1989). Also, the reference population lacked sufficient numbers of specific racial and ethnic groups to consider separate charts.

This graph shows the prevalence of low height-for-age or stunting of recently immigrated refugee children from Southeast Asia in the early 1980s (yellow line) compared to white children (red line). By the 1990s, the prevalence of low height-for-age had declined among Asian children and heights for age were almost identical to that of white children in the United States. This study illustrates the effect of environmental factors on growth. Changing socioeconomic status often is associated with improved growth.