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ORIGINAL ARTICLE
Growth charts for Down’s syndrome from birth to 18
years of age
Å Myrelid, J Gustafsson, B Ollars, G Annerén
.............................................................................................................................
Arch Dis Child
2002;87:97–103
Background: Growth in children with Down’s syndrome (DS) differs markedly from that of normal chil-
dren. The use of DS specific growth charts is important for diagnosis of associated diseases, such as
coeliac disease and hypothyroidism, which may further impair growth.
Aims: To present Swedish DS specific growth charts.
Methods: The growth charts are based on a combination of longitudinal and cross sectional data from
4832 examinations of 354 individuals with DS (203 males, 151 females), born in 1970–97.
Results: Mean birth length was 48 cm in both sexes. Final height, 161.5 cm for males and 147.5 cm
for females, was reached at relatively young ages, 16 and 15 years, respectively. Mean birth weight
was 3.0 kg for boys and 2.9 kg for girls. A body mass index (BMI) >25 kg/m2at 18 years of age was
observed in 31% of the males and 36% of the females. Head growth was impaired, resulting in a SDS
for head circumference of −0.5 (Swedish standard) at birth decreasing to −2.0 at 4 years of age.
Conclusion: Despite growth retardation the difference in height between the sexes is the same as that
found in healthy individuals. Even though puberty appears somewhat early, the charts show that DS
individuals have a decreased pubertal growth rate. Our growth charts show that European boys with
DS are taller than corresponding American boys, whereas European girls with DS, although being
lighter, have similar height to corresponding American girls.
Down’s syndrome (DS) is the most common chromo-
somal disorder, with an incidence of about 1/800 live
births in Sweden.12It is associated with mental retarda-
tion and congenital malformations, especially of the heart.3DS
is also characterised by dysfunction/disease in several other
organs.45
Short stature is a cardinal feature of DS.6The growth retar-
dation of children with DS commences prenatally.7After birth
growth velocity is most reduced between 6 months and 3 years
of age.68Puberty generally occurs somewhat early and is asso-
ciated with an impaired growth spurt.69
Statural growth is a well known indicator of health during
childhood. As growth and final height differ markedly
between children with DS and healthy children, standard
growth charts should not be used for children with DS. If the
growth of a child with DS is plotted on a standard growth
chart, the development of an additional disease, such as hypo-
thyroidism or coeliac disease, may be overlooked.
Several syndrome specific growth charts have been
developed.6 10–15 Previously published growth charts for DS are
based on American,610Sicilian,11 and Dutch12 populations. The
American DS growth charts6are frequently used all over the
world. As we have shown earlier that the mean final height of
Swedish boys with DS exceeds that of corresponding
American boys,9and as the reported difference in final height
between the American boys and girls was low,6there was a
need for new DS growth charts. Thus, the aim of this study
was to create growth charts for Swedish children with DS and
to compare these with the presently used DS growth charts of
Cronk and colleagues6and the Swedish standard growth
charts of Karlberg and colleagues.16
MATERIALS AND METHODS
The study is based on data from 4832 examinations of 354
children and young adolescents with DS, 57% males and 43%
females. The children were born between 1970 and 1997. Data
from 203 children (120 males, 83 females) with DS were col-
lected from records on all individuals with DS of four different
paediatric units in Sweden (Uppsala University Children’s
Hospital, Danderyd Central Hospital, Eskilstuna Central Hos-
pital, and the Halmstad County Hospital). Another set of data
was obtained from 151 children (83 males, 68 females) with
DS, whose parents responded to an appeal in a journal for
parents of mentally handicapped children. The only children
who were excluded were 10 patients who had earlier been
treated with growth hormone within a study. Thus, all other
children, regardless of complicating disease such as congenital
heart defect and hypothyroidism, were included. The number
of observations per child differed somewhat between the two
groups (table 1), but there was no observed difference
between the groups in parameters related to growth. The
majority of the children were white and were born in Sweden.
The data used for creation of the growth charts were age at
examination (years and months), height (cm), weight (kg),
and head circumference (cm). Body mass index (BMI, kg/m2)
was also calculated. The growth charts cover the time period
.............................................................
Abbreviations: BMI, body mass index; DS, Down’s syndrome
Table 1 Distribution of the number of children and
the number of observations for the two groups of
Swedish children with Down’s syndrome
Group 1 Group 2 Total
Males
No. of children 120 83 203
No. of observations 1363 540 1903
Females
No. of children 83 68 151
No. of observations 956 571 1527
Group 1: all children living in specified regions of Sweden.
Group 2: children with Down’s syndrome recruited from an appeal.
See end of article for
authors’ affiliations
.......................
Correspondence to:
Dr G Annerén, Department
of Genetics and Pathology,
Rudbeck Laboratory,
Uppsala University, S-751
85 Uppsala, Sweden;
Goran.Anneren@
ped.uas.lul.se
Accepted
19 March 2002
.......................
97
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from birth until 18 years of age, except those for head circum-
ference, which cover the first four years of life.
The data for each sex were divided into 44 different age
groups, one month intervals during the first two years of life,
three months intervals during the third year of life, and one
year intervals thereafter (table 2). Each child contributed only
one single set of data for each age group. If data from more
than one examination within an interval were available, the
figures from the first examination were used.
The growth charts were compared with those presently
used for children with DS, based on American children in
studies by Cronk and colleagues6(height and weight) and
Palmer and colleagues10 (head circumference). A comparison
was also made with the Swedish standard growth charts for
healthy children according to Karlberg and colleagues,16 which
correspond well to those of National Center for Health Statis-
tics (NCHS).17
Table 2 Sample size groupings of the analysed males and females with Down’s syndrome
Males
Age (months) 0 1 2345678910
No. of observations 120 76 68 57 50 55 49 50 38 43 43
Age (months) 11 12 13 14 15 16 17 18 19 20 21
No. of observations 41 48 25 38 26 35 24 20 22 26 16
Age (months) 22 23 24–26 27–29 30–32 33–35
No. of observations 15 19 63 56 45 44
Age (years) 3 4 5678910111213
No. of observations 99 81 47 47 41 46 38 35 34 29 23
Age (years) 14 15 16 17 18
No. of observations 45 35 30 30 35
Females
Age (months) 0 1 2345678910
No. of observations 90 50 48 53 41 39 51 32 31 39 33
Age (months) 11 12 13 14 15 16 17 18 19 20 21
No. of observations 22 55 18 20 17 20 10 40 15 13 18
Age (months) 22 23 24–26 27–29 30–32 33–35
No. of observations 13 13 37 26 31 19
Age (years) 3 4 5678910111213
No. of observations 61 56 45 41 57 47 47 50 42 38 47
Age (years) 14 15 16 17 18
No. of observations 45 44 29 29 37
Figure 1 Growth charts for height (mean (SDS)) of boys with Down’s syndrome from birth to 4 years of age (A) and 3 to 18 years of age (B).
98 Myrelid, Gustafsson, Ollars, et al
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Figure 3 Growth charts for weight (mean (SDS)) of boys with Down’s syndrome from birth to 4 years of age (A) and 3 to 18 years of age (B).
Figure 2 Growth charts for height (mean (SDS)) of girls with Down’s syndrome from birth to 4 years of age (A) and 3 to 18 years of age (B).
Growth charts for Down’s syndrome 99
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Data for weight and BMI were transformed into logarithms
before the statistical analysis in order to obtain normal distri-
butions. All growth charts are based on means and standard
deviations using the weighted regression fitness system
distributed by Jandel.18 The software used was Microsoft Excel
97 SR-1 (Microsoft Corporation, Redmond, WA, USA) and
SigmaPlot, Scientific Graph System, version 3 for Windows
(Jandel Scientific Software, San Rafael, CA, USA).
RESULTS
Figures 1 and 2 present growth charts for height for boys and
girls. Mean birth lengths of both boys and girls with DS were
48 (2.3) cm (figs 1A and 2A), corresponding to −1.5 SD and −1
SD, respectively, on growth charts for healthy Swedish
children.16
The mean final height of males with DS (fig 1B) was 161.5
(6.2) cm (−2.5 SD, Swedish standard16) and that of females
with DS (fig 2B) 147.5 (5.7) cm (−2.5 SD16), resulting in a dif-
ference of 14 cm between the genders. The mean final heights,
when plotted on the growth charts of American children with
DS,6were on the 95th and slightly above the 50th centiles,
respectively. Individuals with DS reached their final height at
relatively young ages, 16 years for males and 15 years for
females (fig 1B and 2B).
Figures 3 and 4 show the charts for weight. The boys had a
mean birth weight of 3.0 (0.6) kg (fig 3A) corresponding to
−1.2 SD.16 The mean weight at 18 years of age was 61 (8.3) kg
(fig 3B) corresponding to −0.4 SD according to the Swedish
standard16 and the 55th centile of American DS growth
charts.6Corresponding figures for females with DS were 2.9
(0.3) kg (−1.5 SD16) and 54 (7.5) kg (−0.5 SD16 and 25th cen-
tile6), respectively (fig 4A and B). A body mass index (BMI)
above 25 kg/m2was observed in 31% of the boys and 36% of
the females at 18 years of age (fig 5A and B).
Figures 6A and B show the increase in head circumference.
At birth, the boys had a mean head circumference averaging
33.0 (1.7) cm, corresponding to −0.5 SD, whereas that at 4
years of age was 48 (1.4) cm, −2.0 SD,Swedish standard.16 The
head circumference of the girls with DS developed in a similar
way with means of 32.5 (1.6) cm at birth and 47.5 (1.2) cm at
4 years of age corresponding to −0.7 SD and −2.0 SD,16 respec-
tively.
DISCUSSION
Syndrome specific growth charts have been developed for sev-
eral different disorders, for example, Down’s syndrome,6 10–12
Turner syndrome,13 Noonan syndrome,14 and Prader–Willi
syndrome.15 These charts are important tools in the medical
care of these children. Short stature is a cardinal sign of
Down’s syndrome. Complicating disorders, such as coeliac
disease, hypothyroidism,and growth hormone deficiency may
aggravate the growth retardation. For detection of additional
growth deviation the use of growth charts specific for children
with DS are necessary. In this investigation we present growth
charts from birth to 18 years of age for children with DS.
The growth pattern is characterised by an impaired growth
velocity from birth until adolescence, especially during the age
interval of 6 months to 3 years and during puberty. In
comparison with healthy boys, the males with DS had mean
birth length and final height at 18 years of age corresponding
to −1.5 SD and −2.5 SD,16 respectively. When the present data
were compared to the American DS growth charts6the final
height corresponds to the 95th centile. The rather marked dif-
ference in final height between Swedish and American males
with DS cannot be explained at present, but may be caused by
factors such as ethnic diversity and differences in size of the
study groups.
Figure 6 Growth charts for head circumference (mean (SDS)) of boys (A) and girls (B) with Down’s syndrome from birth to 4 years of age.
Growth charts for Down’s syndrome 101
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The girls with DS in the present study had a mean birth
length of −1 SD and a mean final height, at the age of 18 years,
of −2.5 SD according to the Swedish standard.16 The final
height of the girls with DS was slightly greater than that of the
American girls. Birth lengths for our children with DS could
not be compared with those of the Americans, as the latter
growth charts start at 1 month of age.
The individuals with DS reached their final height at
relatively young ages, 16 years for males and 15 years for
females. This is in agreement with earlier studies in which an
early onset of puberty has been reported.689 Our results also
show that individuals with DS have a reduced pubertal growth
spurt, contributing to the low final height. In contrast to the
American data6our individuals with DS had the same differ-
ence in mean final height between the genders as healthy
individuals.
Certain groups, in which mental retardation is predomi-
nant, such as the Prader–Willi and Bardet–Biedl syndromes,
are predisposed to overweight.19 Despite having a greater mean
final height than their American counterparts, the mean
weight at 18 years among the Swedish males with DS was
close to the 50th centile of the corresponding American males.
The mean weight for Swedish girls with DS was at the 25th
centile of the American growth charts6at the age of 18 years.
Even though one third of the individuals with DS were over-
weight (BMI >25 kg/m2), as defined by the National Institute
of Health (NIH),20 at the age of 18 years the weight and height
data of the American individuals with DS indicate that
overweight is a greater problem in the latter group.
Considering the mental retardation associated with DS the
growth of the head is of great interest. Our results show that
the mean head circumference of the children with DS was
smaller than that of healthy Swedish children, but slightly
greater than that of American children with DS. In agreement
with previous studies there was a gender difference in head
circumference, the male head tending to be larger than the
female.10 11
Although the optimal choice for the creation of growth
charts would be a longitudinal, prospective study based on
repeated examinations of a large and representative group, the
drawbacks with respect to time constraints and logistics make
it a less attractive model. Another way of collecting data is by
multiple and detached examinations at separate ages, but
given 354 children and 4823 examinations such an analysis
would produce less than 15 sets of data in each group which
would not result in reliable growth charts. In the present study
we used both repeated data for each child, as in a longitudinal
study, and several examinations of different children in the
same age group, as in a cross sectional study. This is a common
solution when growth in specific groups with relatively few
subjects is analysed.6122122
No children were excluded from the present study as a
result of additional disorders. Thus, treated hypothyroidism
and coeliac disease should not affect growth to any significant
extent. Congenital heart defects may affect growth, but are
part of the syndrome for 50% of the DS population.23 It has
been shown that differences in mean stature,comparing those
without or with mild congenital heart disease and those with
moderate or severe heart disease, are no greater than 2 cm for
boys and approximately 1.5 cm for girls up until the age of 8
years. The corresponding difference in weight varies between
0.5 and 2 kg.6
To make certain that there was no bias in the selection of
the children in the study, the mean scores and standard devia-
tions of all parameters were compared between the two
groups of children recruited. There were no differences in any
of the parameters related to growth in the children included
by the appeal compared to those from the four paediatric
units.
Since it is not possible to switch from measurement of
supine to standing height at a fixed age in children with DS
there is no gap in height at the age of 2 years as in Swedish
standards for healthy children.16 Only a slight irregularity in
the curve between 2 and 4 years of age was observed.
In the present work we do not report comparisons between
our DS growth charts and the corresponding Dutch and Sicil-
ian growth charts. The Sicilian growth charts are based on a
rather small number of children and cover only the period up
to 14 years of age. The Dutch growth charts for children with
DS are similar to our charts, but are based on less than half the
number of examinations.
Prader–Willi syndrome and DS share many features related
to growth. No differences can be shown during the prepuber-
tal period comparing syndrome specific growth charts for the
two.24 A beneficial effect of growth hormone therapy is well
established in Prader–Willi syndrome25 and may also be of sig-
nificance in treatment of children with DS.24 26–28
Growth is an excellent marker of health status, both on an
individual and population level. This is especially evident in
disorders such as DS, which is associated with the dysfunction
of several organ systems. Short stature is a characteristic fea-
ture of DS, but there is a pronounced individual variation. This
variation is influenced both by genetic factors from the extra
chromosome 21 and inherited parental factors. In addition
concomitant diseases may influence growth. Children with DS
are great consumers of health care and are seen by many dif-
ferent physicians. Growth charts specific for children with DS
are therefore important tools in the medical routine follow up
as well as in the monitoring of growth promoting treatments.
ACKNOWLEDGEMENTS
This study was supported by grants from the Sävstaholm Society, the
Swedish Medical Research Council (Grant No. K00-72X-09748-10A),
the Gillberg Foundation, and the Carl Tesdorpfs Foundation.
.....................
Authors’ affiliations
Å Myrelid, J Gustafsson, Department of Women’s and Children’s
Health, Uppsala University, Uppsala, Sweden
B Ollars, G Annerén, Department of Genetics and Pathology, Uppsala
University
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ARCHIVIST ........................................................................................................
Epidemiology of birthweight
Babies with lower birthweights have higher risks of dying in infancy. Populations with lower mean
birthweights usually have higher infant mortality rates. So is low birthweight, of itself, an adequate
explanation of increased infant mortality? It has been argued that it is not (Allen J Wilcox.
International Journal of Epidemiology 2001;30:1233–41).
If you plot neonatal mortality (y-axis, logarithmic) against birthweight (x-axis) you get a reversed
J-curve with neonatal mortality falling from a very high level at very low birthweights to a minimum at
about 3.5 kg (US data) and then increasing again at higher birthweights. (Optimal birthweight tends to
be somewhat higher than mean birthweight.) Changing circumstances tend to change the level but not
the shape of the curve. Thus, in the USA neonatal mortality fell for all birthweights between 1950 and
1988 so the 1998 curve lies below but parallel to the 1950 curve. (There is, incidentally, no change in the
curve at 2.5 kg so the distinction between low birthweight and normal birthweight is arbitrary). Factors,
such as maternal smoking or high altitude residence, which reduce birthweight in populations simply
shift the reversed-J to the left. This produces the “low birthweight paradox” because low birthweight
babies in the reduced-birthweight group then have lower mortality rates than babies of the same birth-
weight in the standard group. Maternal smoking then appears to be “beneficial” for lower birthweight
babies. Wilcox solves the paradox by plotting neonatal mortality against birthweight z-scores for each
group. It is then found that the neonatal mortality of babies of smoking mothers exceeds that of babies
of non-smoking mothers at all points of the curve. Therefore, maternal smoking reduces birthweight at
all levels but the effect on neonatal mortality is independent of birthweight. Wilcox argues that attention
should be focussed on preterm births either by recording of gestational age or by estimation of the pro-
portion of small preterm births from the “residual distribution” of the birthweight frequency
distribution. (The “residual” distribution is the lower tail lying outside the normal,bell-shaped, curve and
is almost entirely due to small preterm births.)
Two commentators (Ibid: 1241–3 and 1243–4) accept that the low birthweight/normal birthweight
dichotomy is outdated but challenge Wilcox’s conclusions, one because he believes that Wilcox takes too
little heed of the social context and the other because she still believes that birthweight can be informa-
tive about population health.
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