Acta med. scand. Vol. 192, pp. 157-160, 1972

BODY WEIGHT IN SWEDISH BOYS OF 18

Bjorn Ahlborg, Klas Linroth, Bengt Nordgren, Lars-Olof Nordesjo and Rickard SchCle

From the Military Medical Examination Center and the Department of Clinical Physiology, Karolinska sjukhuset, Stockholm, the Enlistment Center, Solna, and the Department

of Clinical Physiology, Akademiska sjukhuset. Uppsula, Sweden

Abstruct. A representative sample of about 3% of practically the whole population of Swedish 18-year-old boys has been examined in connection with enlistment to compulsory military service. The sample consisted of 1789 boys of 18. The variation of body weight (b.wt.) and other body dimensions such as body height (b.ht.), femoral condylar breadth (right side), chest circumference, waist circumference and muscular strength are presented. The predicted b.wt., reference weight (RW), calculated from b.ht. and femoral condylar breadth are shown in Tables. The quotient between measured weight and RW, weight quotient (WQ), is used. The correlation between b.wt. and femoral condylar breadth is higher than that between b.wt. and b.ht. Individual differences, as regards fat and muscular mass of the body, are discussed as reasons why in some cases the b.wt. differs considerably from what is predicted from b.ht. and femoral condylar breadth.

In the autumn of 1965, when testing the new enlistment system introduced in Sweden from 1969, a representative sample of boys of 18 was collected in connection with enlistment for mili- tary service. Among other variables examined were measurements of certain body dimensions such as body weight (b.wt.), height (b.ht.), skeletal growth and chest circumference. Only few cor- responding studies appear to have been published earlier (2, 4, 6, 7).

Because of the size and representativeness of the material, and of its homogeneity regarding sex and age, the results may be of some practical interest.

METHODS Body weight was measured without clothes and reported to the nearest kg. Body height was measured without shoes, reported to the nearest cm. Femorul condvlur breadth was measured with a “Caliper” and reported in mm. Chest circumference (cm) was recorded at mainillary

height after a normal expiration, the subjects standing relaxed with the arms hanging. Waist circumference (cm) was measured immediately above the crista iliaca under the same conditions. The maximal isometric rnuscle strength (kp) on the right side was recorded in hand grip, elbow flexion and knee extension (8).

MATERIAL The material, which is described elsewhere (l), consists of 1789 boys of 18 who constituted a representative sample (3%) randomly selected from the Swedish enlist- ment population (except the counties of Halland and Gotland) in the autumn of 1965.

When presenting relationships between b.wt. and other variables the material has been limited for the same reasons as reported in our stttdy on blood pressure (1). 394 individuals were excluded due to illness or other causes of decreased fitness for service as not being suitable in a normal material. Another 80 individuals were excluded since the examination was not complete on all points. Consequently the reported relationships refer to 1315 individuals.

A comparison has been made between these 1 315 and the excluded 472 individuals. The mean b.wt., femoral condylar breadth and chest circumference were somewhat lower for the 472 excluded individuals than for the remaining group. The differences, 0.53 kg, 0.30 mm and 0.27 cm, respectively, were, however, not significant ( p > 0.2). On the other hand b.ht. and waist circumference were significantly lower ( p i 0.05) for the excluded group. The differences were, however, only 0.72 and 0.61 cm, respectively, between the groups. Thus even the signifi- cant differences in body dimensions between the two groups are so small as probably to have no practical relevance.

The exact mean age has not been calculated. All the subjects were born in the same year (1947). Thus the variation of age is very small.

RESULTS The histogram of b.wt. shows a distribution with a slight positive skewness (Fig. 1). The mean

Acta ined. scand. 192

158 B . Ahlborg et al.

“L

BUD,‘ WEIGH1

X = 66.40

5 : 8.61

n = 1787

44.5 53.5 62.5 71.5 80.5 89.5 530.5

Fig. 1. Frequency distribution of b.wt.

weight is 66.40 kg, S.D. 8.61 kg. The number of individuals is 1787, since information on b.wt. is lacking for two.

The relationships between b.wt. and other variables in the study have been examined. These relationships refer to 1315 individuals and are highly significant ( p < 0.001).

The variation of measured b.wt. with other variables is expressed in Table I.

For different combinations of b.ht. and femoral condylar breadth the b.wt. has been calculated according to equation no. 6 in Table I. This predicted b.wt., “reference weight”, is shown in Table 11. Reference weight is a term first used by Behnke et al. (2). Our reference weight (RW) is calculated from factors not influenced by obesity (b.ht. and femoral condylar breadth). By dividing the measured b.wt. of an individual by

the R W a quotient is obtained which may be called “weight quotient” (WQ), that is

measured weight reference weight (RW)

weight quotient (WQ) =

The WQ is shown in Table 111. To test the result of the use of WQ this

quotient was calculated for 2818 boys of 18 in connection with enlistment in 1968. The distribu- tion of W Q in this material is shown in Fig. 2. As for b.wt., this distribution is a little skew. More than 96% of the material had a WQ within 0.80-1.20.

The relationship between b.wt. and muscle strength has been examined. The following coef- ficients of correlation were obtained:

b.wt.-hand grip (r = 0.42) b.wt.-knee extension (r = 0.39) b.wt.-elbow flexion (r = 0.35)

DISCUSSION

Body weight is dependent both on the dimensions of the body (e.g. height and circumferential meas- urements) and on relative proportions of dif- ferent body tissues. Consequently i t is not SUP- ficient merely to measure the absolute b.wt. when judging whether the b.wt. is “normal” or not.

Deviations in b.wt. may be a sign of disease or deviating habits (e.g. too high or too low calory intake with the food in relation to the combus-

Table I . Relationships between h.wt. and certaiii anthropometric data ( n = 1315, p.: 0.001)

Eq. Eq. of no.a y X1 XY r R regression line s e

B. wt. B. wt. B. wt. B. wt.

B. wt.

B. wt. B. wt.

B. wt.

B. wt.

B. ht. B. ht. Fern. cond. breadth Chest circurn-

Waist circum-

Fern. cond. breadth Muscle strength,

Muscle strength,

Skeletal wcightb

ference

ference

hand grip

hand grip

0.51 0.51 0.62 0.81

0.8 I

B. ht. 0.66 0.42

Fern. cond. 0.66 breadth

0.62

y =. 0.665.~- 5 I .43 7.02

y’ 1.146~-44.75 6.44 y = ~ 1.238~-44.16 4.83

y - 1 . 1 0 9 ~ - 16.93 4.81

y = ~ 0 . 3 9 8 ~ + 150.92 5.43

y =~ 0 . 8 8 9 . ~ ~ + 0 .340 .~~- 80.14 6.18 y-~0.331.r I 45.47 7.41

y = O . 1 8 5 ~ ~ ~ t 0 . 9 9 I . r ~ - 4 0 . 4 6 6.18

y-4.223.~-1 14.87 6.42

a Referred to in the text. According to v. Dobeln’s formula (3).

Actn nied. scuntl. 192

Body weight in boys of I8 159

Table 11. Reference weight ( R W ) ~

Femoral condylar Height (cm) breadth (mm) 140 145 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225

75 80 85 90 95

100 105 110 1 I5 I20 125

34.1 35.8 37.5 39.2 40.9 42.6 44.3 46.0 47.7 49.4 51.1 52.8 54.5 56.2 57.9 38.6 40.3 42.0 43.7 45.4 47.1 48.8 50.5 52.2 53.9 55.6 57.3 59.0 60.7 62.4 43.0 44.7 46.4 48.1 49.8 51.5 53.2 54.9 56.6 58.3 60.0 61.7 63.4 65.1 66.8 47.5 49.2 50.9 52.6 54.3 56.0 57.7 59.4 61.1 62.8 64.5 66.2 67.9 69.6 71.3 51.9 53.6 55.3 57.0 58.7 60.4 62.1 63.8 65.5 67.2 68.9 70.6 72.3 74.0 75.7 56.4 58.1 59.8 61.5 63.2 64.9 66.6 68.3 70.0 71.7 73.4 75.1 76.8 78.5 80.2 60.8 62.5 64.2 65.9 67.6 69.3 71.0 72.7 74.4 76.1 77.8 79.5 81.2 82.9 84.6 65.3 67.0 68.7 70.4 72.1 73.8 75.5 77.2 78.9 80.6 82.3 84.0 85.7 87.4 89.1 69.7 71.4 73.1 74.8 76.5 78.2 79.9 81.6 83.3 85.0 86.7 88.4 90.1 91.8 93.5 74.2 75.9 77.6 79.3 81.0 82.6 84.3 86.0 87.7 89.4 91.1 92.8 94.5 96.2 97.9 78.6 80.3 82.0 83.7 85.4 87.1 88.8 90.5 92.2 93.9 95.6 97.3 99.0 100.7 102.4

59.6 61.3 63.0 64.1 65.8 67.5 68.5 70.2 71.9 73.0 74.7 76.4 77.4 79.1 80.8 81.9 83.6 85.3 86.3 88.0 89.7 90.8 92.5 94.2 95.2 96.9 98.6 99.6 101.3 103.0

104.1 105.8 107.5

tion). The physical activity of the individual also plays a role.

A relationship between obesity and different diseases (with a higher risk of complications and a shorter mean life span) has been reported, e.g. in cardiovascular diseases such as arteriosclerosis and hypertension (5). For evaluation of the prog- nosis of diseases associated with high b.wt., it is essential to be able to decide to what extent the overweight is of importance.

Fat, muscle and bone tissues constitute quanti- tatively essential components of the body. The skeletal tissue in the adult individual is relatively constant, while both the quantity of fat tissue (e.g. due to under- or overfeeding) and muscle mass (dependent on physical activity) may vary.

Table 111. Weight quotient ( WQ)

The specific weight of for example fat differs considerably from that of bone. Consequently the relative proportions of different body tissues influence the b.wt. Direct measurements of the fat content of the body are not possible in mass examinations, in which only a short time is available for each individual.

A measure of the development and dimen- sions of the bone tissue (i.e. the skeleton) is the “sturdiness factor” (6). The sturdiness factor in- cludes the degree of appositional bone growth. In this study the sturdiness factor is expressed as the femoral condylar breadth. Both b.ht. and femoral condylar breadth constitute measures of the skele- tal dimensions of the individual. The b.wt. is, however, more closely correlated to femoral

Measured weight (kg) RW (kg) 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120 125

35 1.00 1.14 1.29 1.43 1.57 1.71 1.86 2.00 2.14 2.29 2.43 2.57 2.71 2.86 3.00 3.14 3.29 3.43 3.57 40 0.88 1.00 1.13 1.25 1.38 1.50 1.63 1.75 1.88 2.00 2.13 2.25 2.38 2.50 2.63 2.75 2.88 3.00 3.13 45 0.78 0.89 1.00 1.1 1 1.22 1.33 1.44 1.56 1.67 1.78 1.89 2.00 2.11 2.22 2.33 2.44 2.56 2.67 2.78 50 0.70 0.80 0.90 1.00 1.10 1.20 1.30 1.40 1.50 1.60 1.70 1.80 1.90 2.00 2.10 2.20 2.30 2.40 2.50 55 0.64 0.73 0.82 0.91 1.00 1.09 1.18 1.27 1.36 1.45 1.55 1.64 1.73 1.82 1.91 2.00 2.09 2.18 2.27 60 0.58 0.67 0.75 0.83 0.92 1.00 1.08 1.17 1.25 1.33 1.42 1.50 1.58 1.67 1.75 1.83 1.92 2.00 2.08 65 0.54 0.62 0.69 0.77 0.85 0.92 1.00 1.0s 1.15 1.23 1.31 1.38 1.46 1.54 1.62 1.69 1.77 1.85 1.92 70 0.50 0.57 0.64 0.71 0.79 0.86 0.93 1.00 1.07 1.14 1.21 1.29 1.36 1.43 1.50 1.57 1.64 1.71 1.79 75 0.47 0.53 0.60 0.67 0.73 0.80 0.87 0.93 1.00 1.07 1.13 1.20 1.27 1.33 1.40 1.47 1.53 1.60 1.67 80 0.44 0.50 0.56 0.63 0.69 0.75 0.81 0.88 0.94 1.00 1.06 1.13 1.19 1.25 1.31 1.38 1.44 1.50 1.56 85 0.41 0.47 0.53 0.59 0.65 0.71 0.76 0.82 0.88 0.94 1.00 1.06 1.12 1.18 1.24 1.29 1.35 1.41 1.47 90 0.39 0.44 0.50 0.56 0.61 0.67 0.72 0.78 0.83 0.89 0.94 1.00 1.06 1 . 1 1 1.17 1.22 1.28 1.33 1.39 95 0.37 0.42 0.47 0.53 0.58 0.63 0.68 0.74 0.79 0.84 0.89 0.95 1.00 1.05 1 . 1 I 1.16 1.21 1.26 1.32

100 0.35 0.40 0.45 0.50 0.55 0.60 0.65 0.70 0.75 0.80 0.85 0.90 0.95 1.00 1.05 1.10 1.15 1.20 1.25 105 0.33 0.38 0.43 0.48 0.52 0.57 0.62 0.67 0.71 0.76 0.81 0.86 0.90 0.95 1.00 1.05 1.10 1.14 1.19 110 0.32 0.36 0.41 0.45 0.50 0.55 0.59 0.64 0.68 0.73 0.77 0.82 0.86 0.91 0.95 1.00 1.05 1.09 1.14

Actu med. scand. 192

160 B . Ahlbnrg el a!.

u.ks O.'AO 0.95 I. 10 1.25 1.40

Fig. 2. Frequency distribution of WQ.

condylar breadth (eq. no. 3) than to b.ht. (eq. no. 1) . Consequently it seems better to use femoral condylar breadth than b.ht. for predic- tion of b.wt. in an individual. The time required for measurement of femoral condylar breadth and b.ht. is small. Therefore, in practical routine work these dimensions can be used for prediction of ordinary b.wt. The method provides rapid in- formation as to whether the absolute individual b.wt. deviates from the ordinary predicted.

To simplify the use of multiple correlation in eq. no. 6 the predicted b.wt. (RW) for different femoral condylar breadths and b.hts. has been calculated in Table 11.

To make it possible to get a rapid quantitative measure of the individual relationship between measured weight and RW the WQ has been calculated (Table 111). In this way individuals with varying height and sturdiness can be com- pared when taking into account differences in the skeletal sturdiness factor and b.ht.

The application of WQ to another group of 18-year-old boys (Fig. 2 ) shows that WQ (using eq. no. 6) constitutes a satisfactory measure for classification of b.wt. Consequently WQ is deter- mined and used when evaluating b.wt. at enlist- ment for compulsory military service in Sweden.

The amount of fat tissue has not been deter- mined. Neither b.ht. nor femoral condylar breadth constitute a measure of the weight of the total body fat. A deviation from 1.00 in WQ may

consequently be caused by a deviation in the individual quantity of fat.

The individual muscle mass cannot be measured directly. The size and strength of the muscle in the different parts of the body are dependent, among other things, on the degree of physical training of the actual muscles. Measurement of muscle strength in different parts of the body, therefore, need not be representative of the individual total muscle mass (8). The reported significant relationships between b.wt. and muscle strength (hand grip, knee extension and elbow flexion) show that, for example, hand grip can be used for prediction of b.wt.

Eq. no. 8 shows the prediction of b.wt. from femoral condylar breadth (the sturdiness factor) and hand grip (muscle factor). A comparison with the relationship b.wt. to femoral condylar breadth and b.ht. (eq. no. 6) shows the same coefficient of correlation and standard error of estimate, i.e. the two relationships are equivalent for prediction of body weight.

REFERENCES

1. Ahlborg, B., Linroth, K., Nordgren, B., Nordesjo, L.-0. & SchCle, R.: Blood pressure in Swedish boys of 18. Acta med. scand. 191: 297, 1972.

2. Behnke, A. R., Feen, B. G. & Welham, W. C.: Specific gravity of healthy men. J.A.M.A. 118: 495, 1942.

3. v. Dobeln, W.: Kroppsstorlek, energiomsattning och kondition. Handbok i ergonomi, p. 245. Almqvist & Wiksell, Stockholm, 1966.

4. Gibbons, B. T., Phillips, I. A,, Budensiek, R. K. & Gilbertson, J. R.: Age, height and weight of 2 173 men entering recruit training during 1952 at the US. Naval Training Center, Great Lakes, Illinois. Project Report NM 003 044.01.01., Naval Medical Research Unit No. 4, 22 June 1953.

5. Kannel, W. B., Le Bauer, E. J., Dawber, T. R. & McNamara, P. M.: Relation of body weight to develop- ment of coronary heart disease: Framingham study. Circulation 35: 734, 1967.

6. LindegSrd, B.: Body-build, Body-function and Personal- ity. Lunds universitets arsskrift N.F. Avd. 2 Bd 52, Nr 4. Kungl Fysiografiska Slllskapets handlingar N.F. Bd 67, Nr 4, 1956.

7. - Variations in human body-build. Acta psychiat. (Kbh.) Suppl. 86, 1955.

8. Tornvall, G.: Assessment of physical capabilities. Acta physiol scand. Suppl. 201, 1963.

Acta rried. scand. 192