Changes in leg length and height during treatment with somatotropin

Transdermal testosterone application: pharmacokinetics and effects on pubertal status, short-term growth, and bone turnover

The aim of the study was to assess the effect of transdermal testosterone on free testosterone concentrations in saliva and on short-term growth and bone turnover in boys with growth or pubertal delay. A prospective, randomized, crossover study was conducted over 26 wk with 4 wk of run-in, 8 wk of treatment I (8 or 12 h), 4 wk of washout, 8 wk of treatment II (8 or 12 h), and 4 wk of final washout. The main outcome measures were salivary testosterone profiles during the different study periods; weekly change in lower leg length (LLL) as measured by knemometry, i.e. LLL velocity; absolute and percentage change in bone alkaline phosphatase (bALP) levels; and deoxypyridinoline cross-links measured in urine. Eight boys who took part in the study had a median age of 13.5 yr (range, 12.4-14.9 yr), testicular volume of 3 ml (range, 2-6 ml), height SD score of -2.4 (range, -1.44 to -3.35), and bone age delay of 2 yr (range, 1-3.2 yr). Median salivary testosterone during 8- and 12-h treatments [179 pg/ml (range, 7-3579 pg/ml) and 150 pg/ml (range, 12-3472 pg/ml) (not significant)] was significantly higher than during the run-in and washout blocks (P < 0.0001) [9 pg/ml (range, <7 to 122 pg/ml) and 13 pg/ml (range, <7 to 285 pg/ml) (not significant)]. LLL velocity in the treatment blocks (median, 0.64 mm/wk; range, 0.1-1.08 mm/wk) was significantly higher than during the run-in and washout periods (median, 0.48 mm/wk; range, -0.06 to 0.92 mm/wk) (P < 0.001). The main rise in bALP occurred during the first treatment block with a median percentage change in bALP of 44.2% (range, -4 to 87%) and a smaller percentage change in bALP at the end of the second treatment block of 9.8% (range, -4 to 55%). The increases in bALP were not significantly different between the 8- and 12-h treatment periods, and there was no significant decline during the washout periods. Overnight transdermal testosterone application, as Virormone (5 mg), may be a potentially acceptable method of induction of puberty and stimulates short-term growth and bone turnover.

Effects of inhaled corticosteroids on growth

Inhaled corticosteroids are an established treatment for asthma in childhood. The risk of adverse events associated with conventional doses of inhaled corticosteroids is low, but in children with asthma concern remains about the potential effects of these compounds on growth. Short-term growth in children can be measured with knemometry. This technique measures changes in lower leg length that can be detected over periods as short as days or even intradaily. However, nonlinearity of lower leg growth and the complexity of statural growth confound any attempts to derive a predicted height from short-term measurements of the lower leg. Knemometry is better at detecting growth suppression than growth promotion. With knemometry, inhaled fluticasone propionate 200 microg/day had no effect on lower leg growth, but beclomethasone propionate 400 microg/day significantly reduced lower leg growth. Inhaled budesonide also caused a dose-dependent reduction in lower leg growth, but this only reached significance at the 800 microg/day dose. Long-term growth in children is measured with stadiometry. Growth velocity can only be determined from measurements of height taken over a period of at least 1 year. There is no evidence that inhaled corticosteroids at conventional doses have an adverse effect on the final height of children, but it is important to be aware of the growth-impairing effect of poorly controlled asthma. All children with asthma receiving inhaled corticosteroids should have their growth monitored, and any deviation from the expected pattern should be investigated. The effect of early intervention with inhaled steroids in childhood warrants further investigation.

A comparison of ultrasonic and mechanical stadiometry

AIM

To compare an ultrasonic height measuring device (Gulliver) with mechanical stadiometry and the classical "book and tape measure" method.

METHODS

Blinded duplicate measurements of height were made on each of 14 children by a pair of observers using a stadiometer (H) and Gulliver (G). Height was measured on a further 18 children by parents and an auxologist using Gulliver and the book and tape method (TM), and the results were compared with those obtained with a single stadiometry measurement. Finally, measurement of a rigid metal box was made on 10 occasions by the three methods.

RESULTS

In the group of 14 children, the mean difference (range) in height (H minus G) was +2.8 cm (+0.5 to +4.55 cm), with H giving a systematically higher value in 276 of 280 individual measurements. In the group of 18 children, height by H was greater than by G or TM in 47 of 52 individual measurements. The mean (SD) height of the box by H (61.60 (0.07) cm) was greater than by G (60.96 (0.15) cm; p < 0.001) but not TM (61.4 (0.16) cm; p > 0.05). G and TM produced three times less reliable estimations of height than H, but with a large difference in cost, and there was evidence of systematic underrecording of height by 0.5 cm with G.

CONCLUSIONS

Stadiometry is precise and reproducible, and can detect true changes in height over one month periods in mid-childhood, and should remain the standard way of observing growth. The book and tape method can produce clinically acceptable quarterly estimations of height that can be performed in the home.

A brief history of the study of human growth dynamics

Human growth is non-linear and short term changes in height velocity cannot be used to predict future growth. This paper discusses the current knowledge of growth dynamics in the context of a historical review of the subject.

Correlations among height, leg length and arm span in growing Korean children

A cross-sectional study was performed to find out if any specific correlations exist among height, leg length and arm span in growing Korean children. Height, leg length and arm span were measured in 10,322 healthy children (4740 males and 5582 females). Computed ratios of leg length to height, leg length to arm span and arm span to height for the 3rd, 25th, 50th, 75th and 97th percentiles were made. It was found that the ratios of leg length to height, leg length to arm span, and arm span to height were bigger in taller children in the same age group than the shorter ones in both sexes. All the ratios were bigger in older children in the same percentile than the younger ones in both sexes, showing that the growth rates of leg length and arm span were bigger than that of height in general. However, growth of leg length is faster in shorter children than in taller children until the onset of puberty, after which growth of leg length in taller children is faster than in shorter children. The first and most rapid growth of leg length is seen from birth to 2 years, the second growth spurt is seen during the pubertal period. An exceptional increment in leg length between ages from 10 to 15 is also noted in taller children. After puberty, arm span grows faster than height until 17 years of age in the tallest male child, and taller children have longer arm span than height, while arm span in the shortest children never exceeds height.

Seasonality in lower leg length velocity in prepubertal children

Despite low measuring error, annual growth is poorly predicted by short-term measurements of the lower leg. In order to study if this low correlation can be explained by seasonal changes in lower leg length (LLL) velocity, we followed short-term growth longitudinally in 50 prepubertal children with normal height and growth velocities. Height measurements were performed at 4-week intervals and LLL measurements at 1-2 week intervals. Analysis of annual growth showed seasonality in the monthly mean height velocity values: 5.06 (SD 5.02) cm/year during the autumn and 8.15 (SD 5.22) cm/year in the spring. Similarly, the monthly mean LLL velocity values changed from 1.80 (SD 1.07) cm/year in the autumn to 2.63 (SD 0.92) cm/year in the spring. The correlation between monthly LLL and annual height velocity was low (r = 0.27). The technical error of the LLL measurement was 7-8% of the mean monthly LLL velocity, while the mean values changed by 31% over the seasons. The annual height velocity was virtually independent of the variation in growth rate over the seasons. It is concluded that there is significant seasonality both in height and LLL velocity and that it takes place at the same time for both measures. Seasonality in LLL has not been reported previously and must be considered when studying short-term growth, for example when LLL is used for prediction of annual height velocity or when a short-term treatment effect is examined using LLL.

Knemometry

Knemometry provides a powerful tool for observation of short-term growth patterns. Failure of response to growth-promoting therapies in the short term predicts a poor statural response, but the relationship of the lower leg growth suppression seen with oral and inhaled corticosteroids, and the clinical implications in the longer term, remain unclear. The accumulating evidence suggests that there are measurable biochemical and clinical effects with some inhaled corticosteroids (e.g. beclomethasone dipropionate and budesonide), when given at the upper end of the recommended conventional dose range (18) and for long-term prophylaxis, and certainly at the higher starting doses. It is imperative, therefore, that all children receiving inhaled corticosteroids should have their growth monitored carefully and that the lowest effective dose of corticosteroid should be used.

Metabolic effects of growth hormone treatment: an early predictor of growth response?

Fourteen children receiving one year of recombinant human growth hormone (rhGH) treatment underwent measurement of serial changes in body composition (measured by skinfold thickness, bioelectrical impedance, and H2(18)O dilution), resting energy expenditure (REE, estimated by ventilated hood indirect calorimetry), and total free living daily energy expenditure (TEE, measured by the doubly labelled water technique). Mean height velocity increased from 4.9 to 8.6 cm/year after six months of treatment. Fat free mass (FFM) increased more during the first six weeks (24.4 g/day) than from six to 26 weeks of treatment (6.8 g/day); fat mass decreased by 7.2 g/day and 1.1 g/day respectively. The six week increase in REE (kJ/day) was maintained after six months of treatment, though expressed per kilogram FFM (kJ/kgFFM/day), returned to pretreatment values by three months. Height velocity increases at six months correlated with six week changes in fat mass measured by skinfold thickness and REE, though use of this relationship to predict growth response in individuals is limited by the wide 95% prediction intervals. No significant changes in growth, body composition, or energy expenditure were observed between six and 12 months of treatment, in either patients who had initially responded well to treatment or those who were poor initial responders to treatment and who had their dose of rhGH doubled after six months.

The application of knemometry in renal disease: preliminary observations

Short-term lower leg length was measured longitudinally using a high-precision device called a knemometer in 11 children with chronic renal failure and 12 normal children. The method has a high accuracy (mean standard error 0.13 mm) and may prove useful for prediction of long-term total body growth. Its application in renal patients undergoing corticosteroid, growth hormone (GH) and erythropoietin (EPO) therapy is documented. GH was shown to improve lower leg growth in an adolescent who already had passed the maximum of his pubertal spurt. EPO treatment produced no consistent increase of short-term growth.