Upper segment/lower segment ratio and armspan–heightdifference in healthy Turkish children

SERAP TURAN, ABDULLAH BEREKET1, ANJUM OMAR1, MUSTAFA BERBER1,

AHMET OZEN1 & NURAL BEKIROGLU2

Department of Paediatrics, Division of Paediatric Endocrinology1 and Department of Biostatistics2, Marmara University,

School of Medicine, I.stanbul, Turkey

AbstractAim: The determination of body proportions is an important part of the clinical evaluation of children with short stature. Theupper segment/lower segment ratio (US/LS ratio) and armspan–height difference is commonly used for this purpose.However, reference data are scarce in this respect, and available standards do not include standard deviations for themeasurements. We aimed to establish the normal values for upper segment/lower segment ratio and armspan–heightdifference in Turkish children. Methods: In the present study, height, upper and lower segment, and armspan were measuredin 1302 healthy children (3–18 y). The age-related mean and standard deviation curves of the US/LS ratio and armspan–height difference were constructed for each sex. Results: The mean values of the US/LS ratio in boys were decreased from1.108 at 3 y to 0.984 at 10 y. The nadir of the US/LS ratio (0.922) was reached at age 15 y. In girls, the mean value of theUS/LS ratio gradually decreased to less than 1 at 9 y of age (1 y earlier than in boys). The nadir of the US/LS ratio (0.946) wasreached at age 13 y in girls (2 y earlier than in boys). Armspan was shorter than height as expected in younger ages, but becameslightly longer at around age 12 in girls and boys. Unlike boys, the armspan–height difference did not change much afterpuberty in girls.

Conclusion: US/LS ratio and armspan–height difference are practical parameters and easy to perform in any setting. Wehope that these standards will aid clinicians in the evaluation of children with short stature.

Key Words: Anthropometry, armspan, auxology, body proportions, upper segment/lower segment ratio

The evaluation of a child with short stature begins with

anthropometric measurements. After establishing the

degree of shortness, the next step would be to decide

whether the child is proportionately or disproportio-

nately short. The first step is easily performed as charts

for height and weight measurements are available for

a variety of populations. However, data are scarce for

population-specific standards for body proportions.

Such data are helpful for the differential diagnosis of

short stature. If the child is diagnosed with dispropor-

tional short stature, the third step would be to deter-

mine the source of disproportionality (i.e. short trunk

or short extremities).

For practical reasons, upper segment/lower segment

ratio (US/LS ratio) and armspan–height difference

are among the most commonly used parameters for

assessing body proportions. However, the reference

values for these measurements found in a few endo-

crinology and auxology textbooks are relatively old

and derived from North American children [1]. Al-

though these standards may be of value in diagnosing

extreme forms of disproportionate short stature such

as achondroplasia, population-specific standards are

required for diagnosis of more subtle forms of dispro-

portionate short stature such as hypochondroplasia,

etc. In addition, more careful and precise assessment

is needed in younger patients when body proportions

are not yet severely distorted. Specific standards are

required not only for clinical practice but also for

studies investigating the effect of different anabolic

therapies on body proportions in children with a variety

of growth disorders, including more common forms

of growth disorders such as constitutional delay in

growth and adolescence.

Correspondence: Abdullah Bereket, Bozkir Sokak No. 4/7 Selamicesme, _IIstanbul, Turkey. Tel: +90 216 327 10 10 ext. 577. Fax: +90 216 651 00 44.

E-mail: abereket@e-kolay.net

(Received 8 March 2004; revised 12 July 2004; accepted 30 July 2004)

Acta Pædiatrica, 2005; 94: 407–413

ISSN 0803-5253 print/ISSN 1651-2227 online # 2005 Taylor & Francis Group Ltd

DOI: 10.1080/08035250410023269

Currently, no published standards for US/LS ratio

and armspan–height difference in the Turkish popu-

lation exist. Therefore, foreign standards (obtained

from different ethnic groups) are being used in clinical

practice. However, due to differences in anthropo-

metric characteristics, pubertal maturation rate and

“the secular trend” in different countries, population-

specific standards must be established. This study

was intended to provide reference data for US/LS ratio

and armspan–height difference in healthy Turkish

children.

Subjects

This study was designed as a cross-sectional study and

conducted by permission of the local ethic committee

and Ministry of National Education.

One thousand, four hundred and twenty-eight

school children, aged 3 to 18 y, were sampled in three

elementary schools, two high schools and four day

nurseries in Istanbul. A questionnaire regarding the

medical history of each child was completed by the

parents a week prior to the measurements. One thou-

sand, three hundred and two subjects were included

in the final analysis, after excluding children with

short stature, malnutrition, chronic systemic diseases,

history of prematurity or those with history of intra-

uterine growth retardation or intake of medications

known to effect growth.

Material and methods

All measurements were performed by a team of two

paediatric endocrinologists and three paediatricians.

Team members were trained before the study to ensure

the precision of the measurements. Calculated preci-

sion indexes were: for height: r=0.999, technical error

of measurement (TEM)=0.0008, CV=7.48%; for

lower segment: r=0.998, TEM=0.0097, CV=9.4%;

for armspan: r=0.999, TEM=0.007, CV=9.9%.

Height was measured with a stadiometer. The

subject was measured without shoes, ensuring that

the heels, buttocks and occiput were in contact with the

vertical measure. Head tilt was avoided by instructing

the child to look straight ahead, which brought the

lower margin of the eye socket to the same level as

the external auditory meatus (Frankfurt plane). The

child was then stretched gently by upward pressure

under the mastoid processes and instructed to relax

the shoulders.

The lower segment was measured after the height

measurements were completed. The child stayed in

the same position, except the feet were spaced 4 cm

apart to facilitate the measurement. Position of the

symphysis pubis was detected by palpation. The dis-

tance from the top of the symphysis pubis to the floor

was measured by a vertical ruler (lower segment). The

upper segment was calculated by subtracting the lower

segment value from the height. The US/LS ratio was

obtained by dividing the upper by the lower segment.

Armspan was measured with the child standing

straight against a wall while the arms were maximally

stretched horizontally (making a 90� angle with the

trunk) and the tips of the middle fingers were marked

on the wall. The distance between the tips of the

middle fingers was then measured by a tape measure.

All of the measurements were repeated several times

by the same observer, and the mean of the measure-

ments was taken as the final value.

Statistical methods

After calculating descriptive statistics (mean, SD) for

each age and sex group, scatter diagrams of the data

were constructed. Age was taken as an independent

variable, while US/LS ratio and armspan–height

difference were taken as dependent variables. The

distribution of the data was analysed by the curve-

fitting method. Second-degree polynomial distribution

gave the best fit for both measurements. Age-related

means and standard deviation curves of the US/LS

ratio and armspan–height difference were constructed

for each sex.

Results

The mean values of the US/LS ratio in boys decreased

from 1.108 at 3 y to 70.984 at 10 y. The nadir of the

US/LS ratio (0.922) was reached at age 15 y. In girls,

the mean values of the US/LS ratio gradually decreased

from 1.098 to less than 1 at 9 y of age (1 y earlier than

boys). The nadir of the US/LS ratio (0.946) was

reached at age 13 (2 y earlier than boys). The curves

for the US/LS ratio are shown in Figures 1 and 2, and

standard deviations in Tables I and II.

Armspan was shorter than height as expected at

younger ages but became slightly longer than height

at around age 12 in girls and boys. In boys, the mean

armspan–height difference was 71.1 cm at 3 y, which

gradually increased and reached 1.98 cm at age 18 y.

In girls, the mean value of the armspan–height differ-

ence was 72.53 at 4 y of age and increased to +0.78

at 12 y of age. Unlike boys, the armspan–height

difference did not change much after puberty in girls.

The curves for the armspan–height difference are seen

in Figures 3 and 4, and the standard deviations in

Tables III and IV.

Positive correlations were detected between height

and armspan (r=0.989 and 0.985), height and lower

segment (r=0.987 and 0.980), armspan and lower

segment (r=0.982 and 0.972), height and armspan–

height difference (r=0.255 and 0.139), and upper

segment and lower segment (r=0.93 and 0.91) in

408 S. Turan et al.

boys and girls, respectively. Negative correlations

were detected between height and US/LS ratio (r=70.663 and 70.501), armspan and US/LS ratio

(r=70.681 and 70.520), and US/LS ratio and

armspan–height difference (r=70.320 and 70.253)

in boys and girls, respectively. The correlation curves

for boys are shown in Figures 5, 7 and 9 for boys, and

in Figures 6, 8 and 10 for girls. Higher correlation

coefficients were observed for boys in all parameters

measured.

Discussion

Determination of body proportions provides useful

information about disproportionate short stature.

Upper segment/lower segment ratio (US/LS ratio)

and armspan–height difference are among the most

frequently used anthropometric measurements to

assess body proportions. However, few studies describe

reference values for body proportions in children.

Furthermore, as for height measurements [2], body

proportions also show inter-racial differences. Thus,

population-specific reference values and charts must

be formed for body proportions as well.

In this study, reference charts were established for

both US/LS ratio and armspan–height difference

for Turkish children. Mean US/LS ratio decreased

from *1.1 in both sexes to a nadir of 0.92 in boys at

age 15 y and 0.95 in girls at age 13 y. These numbers

are in accordance with a widely used US/LS ratio

curve obtained from North American children showing

that US/LS ratios decline from 1.05 at 4 y to *0.92 at

12 y [3]. However, that curve does not take sex and

race into consideration, as it was developed from a

Table I. Upper segment/lower segment ratios in healthy Turkish

boys.

Age (y) n +2 SD +1 SD Mean 71 SD 72 SD

3 23 1.24 1.17 1.11 1.04 0.98

4 25 1.22 1.15 1.09 1.02 0.95

5 23 1.09 1.05 1.00 0.96 0.92

6 32 1.19 1.12 1.06 0.99 0.93

7 34 1.19 1.11 1.04 0.97 0.90

8 42 1.14 1.08 1.02 0.96 0.90

9 48 1.10 1.05 1.01 0.96 0.91

10 56 1.11 1.05 0.98 0.92 0.86

11 59 1.07 1.02 0.97 0.92 0.87

12 37 1.05 0.99 0.93 0.88 0.82

13 48 1.03 0.99 0.94 0.89 0.85

14 85 1.07 1.00 0.94 0.88 0.81

15 73 1.01 0.97 0.92 0.88 0.83

16 45 1.02 0.97 0.93 0.88 0.83

17 36 1.04 0.99 0.94 0.89 0.84

18 9 1.07 1.00 0.94 0.88 0.82

Table II. Upper segment/lower segment ratios in healthy Turkish

girls.

Age (y) n +2 SD +1 SD Mean 71 SD 72 SD

3 16 1.23 1.16 1.08 1.01 0.94

4 23 1.17 1.12 1.07 1.03 0.98

5 17 1.15 1.09 1.04 0.98 0.92

6 30 1.19 1.12 1.04 0.97 0.89

7 37 1.18 1.10 1.01 0.93 0.85

8 45 1.12 1.06 1.01 0.95 0.90

9 42 1.08 1.04 0.99 0.95 0.90

10 46 1.11 1.05 0.98 0.91 0.84

11 70 1.08 1.03 0.97 0.92 0.86

12 41 1.06 1.01 0.95 0.90 0.84

13 59 1.06 1.00 0.95 0.89 0.83

14 51 1.07 1.02 0.97 0.92 0.87

15 56 1.09 1.04 0.99 0.94 0.89

16 38 1.07 1.02 0.97 0.91 0.86

17 19 1.07 1.03 0.98 0.93 0.88

Figure 1. Upper segment/lower segment ratio in healthy children

(boys).

Figure 2. Upper segment/lower segment ratio in healthy children

(girls).

Reference values for body proportions 409

population of 1015 children, black and white, girls

and boys combined. Unlike that curve, our curves

were constructed for boys and girls separately, which

permits more precise assessment of sex- and puberty-

related changes in body proportions. Another standard

that is still in use for North American children,

originally published in Lawson Wilkins’s textbook in

1966, shows that the average US/LS ratio at 4 y is

1.24 and 1.22 in boys and girls, respectively, which

gradually decreases to a nadir of 0.95 in boys but

remains around 1.0 in girls [4]. A newer standard given

in the Harriet Lane Handbook also shows that the

average US/LS ratio declined from *1.25 at age 3 y

to *1.0 at age 14 y [5]. However, these two North

American references do not provide standard devia-

tions for the measurements. Thus, although they

describe what is normal, they do not describe what

is abnormal.

Another way of determining the upper to lower

segment ratio is to measure sitting height and sub-

ischial leg length. This ratio is *1.4 in boys and 1.35 in

girls at age 4 y, which decreases to *1.1 in both sexes

in Dutch children [6]. The requirement of special

equipment for sitting height measurements makes it

less practical for routine use. However, a simple tape

measure and a stadiometer are enough for measure-

ment of the US/LS ratio. Thus, general paediatricians

can evaluate the disproportionality of body segments

without needing sophisticated devices by using

standards presented in this study.

Measurement of only the US/LS ratio for assessment

of body proportions can be misleading since the ratios

of two individuals may be equal while their nominators

and denominators are not equal. Furthermore,

decreased US/LS ratio can be due to an abnormally

short trunk or abnormally long legs. Therefore, it is

important to have at least two parameters to detect

atypical body proportions. Armspan measurement is

a good complimentary parameter for assessing body

proportions. Armspan is shorter than height in

conditions like achondroplasia or Leri-Weill dyschon-

drosteosis in which the growth of the long bones is

primarily affected. Armspan–height difference in our

study was *72 cm in girls at 4 y and became equal

Figure 3. Armspan–height difference in healthy children (boys). Figure 4. Armspan–height difference in healthy children (girls).

Table III. Armspan–height difference in healthy Turkish boys.

Age (y) n +2 SD +1 SD Mean (cm) 71 SD 72 SD

3 23 5.47 2.20 71.07 74.34 77.61

4 25 3.75 1.39 70.97 73.33 75.69

5 23 5.54 2.51 70.52 73.55 76.58

6 32 5.71 2.40 70.92 74.23 77.55

7 34 5.64 2.52 70.59 73.70 76.81

8 42 5.79 2.75 70.28 73.32 76.35

9 48 5.52 2.73 70.06 72.85 75.64

10 56 4.99 2.00 70.98 73.97 76.95

11 59 5.97 2.60 70.77 74.14 77.50

12 37 6.20 3.22 0.25 72.73 75.70

13 48 8.76 4.82 0.88 73.06 76.99

14 85 9.11 5.39 1.67 72.05 75.77

15 73 8.34 5.05 1.76 71.53 74.81

16 45 10.11 5.99 1.87 72.25 76.37

17 36 8.25 4.80 1.34 72.11 75.57

18 9 9.07 5.52 1.98 71.57 75.12

Table IV. Armspan–height difference in healthy Turkish girls.

Age (y) n +2 SD +1 SD Mean (cm) 71 SD 72 SD

3 17 4.20 1.11 71.99 75.08 78.18

4 25 2.44 70.05 72.53 75.01 77.49

5 19 5.94 2.20 71.55 75.30 79.05

6 32 4.63 1.62 71.39 74.40 77.42

7 36 5.67 2.39 70.89 74.17 77.45

8 45 5.82 2.24 71.33 74.90 78.47

9 43 6.71 3.40 0.10 73.20 76.51

10 46 5.46 2.60 70.26 73.12 75.98

11 70 6.13 2.64 70.85 74.34 77.82

12 41 6.65 3.72 0.78 72.16 75.09

13 56 6.53 3.40 0.26 72.87 76.01

14 54 7.28 3.90 0.51 72.87 76.26

15 58 8.49 4.40 0.31 73.79 77.88

16 38 6.12 2.60 70.93 74.46 77.99

17 19 6.55 3.33 0.11 73.12 76.34

410 S. Turan et al.

to height at 9 y. In boys, armspan–height difference

started from 71.1 and gradually increased to *+2 cm

after puberty. The data regarding armspan–height

difference are scarce in the literature. Engelbach

reported an average armspan–height difference of

73.0 and 73.5 in boys and girls, respectively, at age

4 y, with values reaching 0 at 9 y in boys and 12 y in

girls [7]. As in our study, boys had greater armspan–

height difference compared to girls at age 18 y.

The differences between our standards and those

older studies can be explained by a racial and secular

trend. The racial effect on body segments has also been

demonstrated between White and African Americans

[3]. In Brazilian children, it was demonstrated that

the decline of the mean for US/LS ratio from light

to medium to dark children behaves as a polygenic

quantitative trait. Armspan also increased from

light- to dark-skinned children in that study [8]. A

secular trend was also observed in height and body

proportions in the same population in different de-

cades. The increases in height over the years in certain

populations have been found to be mainly due to the

increase in leg length and not due to an increase in

trunk length [9,10]. In a Norwegian study [11], only

20% of the secular increase in height in the period

1921–1962 was related to sitting height, while for

Japanese children the effect of the secular trend from

1957 to 1977 was completely due to increased leg

length [12,13]. In addition to a significant trend

towards greater relative long-leggedness, Ali et al.

Figure 5. Relationship between height and armspan in boys.

Figure 6. Relationship between height and armspan in girls.

Reference values for body proportions 411

Figure 7. Relationship between height and upper/lower segment ratio in boys.

Figure 8. Relationship between height and upper/lower segment ratio in girls.

Figure 9. Relationship between upper segment and lower segment in

boys.

Figure 10. Relationship between upper segment and lower segment

in girls.

412 S. Turan et al.

demonstrated earlier spurt in leg length compared to

spurt in total height in post-war Japan [14].

Differences in height among various socio-economic

classes are also found to be mainly due to an increase in

leg length rather than an increase in sitting height [15].

After immigration to the United States, height and leg

length increased in Guatemalan children [16]. Height

and lower segment measurements were highly corre-

lated in our study as well.

We conclude that the present curves will facilitate

the diagnosis of subtle forms of disproportionate

short stature and will serve as references for both

clinicians and researchers. However, in light of the

above-mentioned studies, reference curves for upper

segment/lower segment ratio and armspan–height

difference should be revised every 20 y to reflect

changes due to secular trends.

Acknowledgements

This work has been supported by the Turkish Academyof Sciences within the framework of the Young ScientistAward programme (EA/TUBA-GEBIP/2001-1-1). Wethank Mehmet Sungur and Merter Burmak for their helpwith statistical analyses, and Dr T. A. Wilson for reviewingthe manuscript.

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Reference values for body proportions 413