Growth references

Abstract

A growth reference describes the variation of an anthropometric measurement within a group of individuals. A reference is a tool for grouping and analyzing data and provides a common basis for comparing populations.1 A well known type of reference is the age-conditional growth diagram. The traditional height-for-age (HfA) diagram shows how height varies both within and across age. Figure 11.1 is the official Dutch diagram of height and weight for Dutch boys aged 1–21 years.2,3 In the HfA diagram, the vertical distance of shaded area in the graph delineates the variation in heights between 2 and 2 standard deviations (SD). The interval between the 2 and 2 SD curves contains about 95.4 percent of all individuals of the same age in the reference sample. The graph at the top displays the variation of weight as a function of height. For reasons that will be discussed in the section ‘Detection of growth disorders’ on p. XX, the shaded area is chosen here between the 1 and 1 SD curves. Anthropometry is an extraordinary good tool for gauging health and well-being in both individuals and in populations. 4 Height and weight are cheap and easy to measure, and provide an almost universal appraisal for assessing children’s well-being. Height is one of the very few positive health indicators. A secular shift in height is a sensitive indicator of socio-economic and socio-medical changes, and thus allows comparisons of the health status of different populations. In fact, secular shifts in height may provide a better and more relevant measure for the detection and evaluation of possible changes in living conditions than such vague concepts as ‘income per capita’ and ‘national product’. 5 Weight is clearly relevant for evaluating both undernutrition and obesity. Both are important problems on a global level. Besides height and weight, many other useful anthropometric measures exist, but the present chapter will concentrate on height, weight and derivates thereof.