Growth charts compared.

Growth assessment of children requires comparison of growth measurements with normative references, usually in the form of growth charts. Traditionally growth charts (growth references) have described the growth of children who were considered normal and were living in a defined geographic area. The new WHO growth charts, on the other hand, are growth standards that aim to represent growth as it occurs worldwide. Moreover, they represent growth as it occurs under optimal circumstances and is thought to be conducive to optimal long-term health. Most growth references are single-country references, exemplified here by charts from the UK, the Netherlands and the USA. By contrast, the Euro-Growth reference and the WHO standard are based on multinational samples. Comparison of these five charts reveals surprisingly large differences that are for the most part unexplained. Differences between the WHO charts and other charts are only partially explained by the use of a prescriptive approach and by the data truncation employed. The large differences between charts probably are of merely trivial consequence when charts are used in monitoring individual children. When charts are used in health assessment of groups of children, the impact of the differences, however, is substantial.