Normal growth in the short normal prepubertal child: The Wessex Growth Study

Abstract

Objective - The study aimed at defining the normal rate of growth for short, prepubertal children, and comparing their pattern of growth with those of average stature. Setting - Community based. Design - Observation of an unselected population of 109 very short, normal pre-pubertal children (<3rd height centile) and 107 controls matched for age and sex (10th to 90th centile). Main outcome measures - Height, velocity, change in height standard deviation score, from 6 to 9 years of age. Results - The absolute mean rate of growth was significantly different between groups - short normal 5.3 cm/year, controls 5.9 cm/year - corresponding to velocities on the 25th and 50th centiles, respectively. The relative growth rates, however, as shown by the changes in height standard deviation score (short normal 0.10 (SD 0.22), controls 0.10 (SD 0.24) did not differ, and each group remained close to its original 3rd and 50th centiles. Two short children showed 'catch up' growth after adoption, but, otherwise, the divergence from their original height centile was the same for short normal and control children. No social or biological factors were found to predict growth rate in the short normal children, and only target height in controls. 'Normal' velocity is conditional on height. Short normal children do grow more slowly than children of average stature, but they do not necessarily grow more poorly. From 6 to 9 years of age they are no more likely to fall off their height centiles than children of average stature. The value of height monitoring at this age is questioned.