On the construction of the infancy-childhood-puberty growth standard.

Using the infancy-childhood-puberty (ICP) growth model, the postnatal linear growth curve is mathematically broken down into three components: infancy, childhood and puberty. The fact that each component of this model seems to represent a defined biological phase of the growth process, extends its clinical application. The principles used to construct the ICP growth standard and the basic 'clinical' ICP-based growth charts are described. These charts have a number of advantages over the conventional growth charts currently in use. Most importantly, the ICP growth chart provides reference values not only for total growth but also for each of the three individual components. Using this methodology, the magnitude and the onset of each component can be assessed in an individual child. The age at onset of the childhood component, which is a newly discovered and important feature of human growth, can easily be detected in an individual child. Furthermore, prepubertal growth, onset of puberty and pubertal growth can be accurately assessed, because the difference in pubertal maturation is taken into account when setting standards during adolescence. The methodology also offers a new and highly accurate predictor of final height and permits assessment of growth rates over shorter and longer periods using a simple and effective method of assessing change. The ICP growth model appears to be a refined instrument for detecting and understanding growth disturbances.