The objective of this study was to create a series of curves which would describe the growth in height and weight, from birth to adulthood, of the populations of different countries throughout the world. The study was based on existing literature and was therefore subject to the constraints imposed by that literature.
The most serious of these constraints is that the published data do not represent the total variation within and between the populations of different countries or geographical regions. Some countries have not been studied at all whilst, for others, we have data for only very small samples which may not be typical of the whole population. From some of the more remote parts of the world we have data for small isolated tribes which are of particular interest to anthropologists but we have no information about the larger populations which are the subject of this investigation. Thus, even in the case of those countries for which data exist, we must question their validity as a measure of the total population.
A further constraint is the complexity of the interaction between genetic and environmental factors in the regulation of growth. Because of this inter-action, we cannot fill in gaps in our information by assuming that populations which are genetically similar will exhibit similar growth patterns or that, conversely, genetic differences will be reflected in growth. Genetically similar populations in different regions may have very different nutrition, patterns of disease, culture and socio-economic circumstances which result in their exhibiting quite different patterns of growth. Reports of growth studies seldom give enough information to permit an accurate judgement of the relative effects on different populations of the various environmental factors which may influence growth.
Furthermore, similarity of growth pattern cannot be assumed on the basis of geographical proximity as populations within a small area may show greater differences in stature than others in widely separated regions.
Thus the literature clearly does not permit the construction of growth curves which can be applied with confidence to all the world's populations. In the light of this fact, the objective of the study was re-defined, following discussion with Dr. Perisse and his colleagues at the Food and Agricultural Organisation. The revised objective was to create a series of curves, each of which would provide an approximate description of the growth of a number of countries for whom reasonably representative data exist. Countries with less complete but reliable data would also be matched approximately with one or other of these curves.
