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CDC Growth Charts:
United States
Introduction
The growth charts consist of a series of percentile curves
that illustrate the distribution of selected body measurements in U.S.
children. Pediatric growth charts have been used by pediatricians, nurses,
and parents to track the growth of infants, children, and adolescents in
the United States since 1977. The 1977 growth charts were developed by the
National Center for Health Statistics (NCHS) as a clinical tool for health
professionals to determine if the growth of a child is adequate. The 1977
charts were also adopted by the World Health Organization for
international use.
When the 1977
NCHS growth charts were first developed, NCHS recommended that they be
revised periodically as necessary. With more recent
and comprehensive national data now available, along with improved
statistical procedures, the 1977 growth charts were revised and updated to
make them a more valuable clinical tool for health professionals. The 2000
CDC growth charts represent the revised version of the 1977 NCHS growth
charts. Most of the data used to construct these charts come from the
National Health and Nutrition Examination Survey (NHANES), which has
periodically collected height and weight and other health information on
the American population since the early 1960's.
Growth charts are not
intended to be used as a sole diagnostic instrument. Instead, growth
charts are tools that contribute to forming an overall clinical impression
for the child being measured. The revised growth charts provide an
improved tool for evaluating the growth of children in clinical and
research settings.
The 2000 CDC Growth Charts
and the New Body Mass Index-For-Age Charts
The revised growth charts consist of 16 charts (8 for boys
and 8 for girls). These charts represent revisions to the 14 previous
charts, as well as the introduction of two new body mass index-for-age
(BMI-for-age) charts for boys and for girls, ages 2 to 20 years.
Most of the specific
differences between the revised charts and the original charts occur in
the charts for infants, where national data were previously lacking. The
revised head circumference charts also show some noticeable differences
when compared to the earlier charts. Compared to the original infant
charts that were based on primarily formula-fed infants, the revised
growth charts for infants contain a better mix of both breast- and
formula-fed infants in the U. S. population. (On average, since 1970
approximately one-half of children born in the United States are reported
to have been breast fed at some point, and about one-third have been
breast fed for 3 months or more.) The addition of the BMI charts is
probably the single most significant new feature of the revised growth
charts.
These BMI-for-age
charts were created for use in place of the 1977 weight-for-stature
charts. BMI (wt/ht2) is calculated from weight and height
measurements and is used to judge whether an individual's weight is
appropriate for their height. BMI is the most commonly used approach to
determine if adults are overweight or obese and is also the recommended
measure to determine if children are overweight. The
new BMI growth charts can be used clinically beginning at 2 years of age,
when an accurate stature can be obtained.
In recent years, BMI
has received increased attention for pediatric use. In 1994, an expert
committee charged with developing guidelines for overweight in adolescent
preventive services (ages 11-21 years) recommended that BMI be used
routinely to screen for overweight adolescents. In addition, in 1997 an
expert committee on the assessment and treatment of childhood obesity
concluded that BMI should be used to screen for overweight children, ages
2 years and older, using the BMI curves from the revised growth charts.
BMI can also be used to characterize underweight (though no expert
guidelines exist for the classification of underweight based on BMI).
Further information
about the revision process can be found on the growth
charts website. |
