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6. Issues regarding the use of condition-specific
growth charts
6.1 Limitations
of specialized growth charts
The usefulness of
specialized growth charts is limited by a number of factors:
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Developed
from very small samples |
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Data
do not reflect racial, ethnic, or geographical diversity |
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Old
data used to construct the charts |
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Difficult
to be sure that the data are representative of the population as a
whole or come from a well-nourished group of children within that
population |
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Inconsistent
measuring techniques used (in some cases, chart reviews were used
to collect data; for other cases, the measurement techniques were
not clearly defined) |
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Secondary
medical conditions which influence growth potential (and which often
accompany a primary chromosomal disorder) not considered |
The charts based on
the growth of children with
trisomy 21 provide some examples of these limitations. (Because trisomy
21 is a chromosomal anomaly, growth potential is altered, and the development
of reference data based on this alteration is reasonable.) The clinician
using the special charts should be aware of limitations:
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The
children in the sample were of limited diversity with respect to race,
ethnicity and the geographic location of their residence. |
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The
nutritional status of the children in the sample was not assessed,
so it is difficult to ascertain whether or not the data represent
a well-nourished group of children or reflect problems with nutritional
status. |
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The
existence of secondary medical conditions affecting growth (congenital
heart disease, which affects about 40% of children with trisomy 21,
and feeding problems, which are present in up to 80% of children with
trisomy 21) was not considered in developing the reference data. |
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