BACKGROUND Reference percentile curves are usually used as a screening tool to determine growth disorders. Anthropometric indices are population-dependent and may differ according to ethnicity, dietary pattern and lifestyle habits. This study aims to compare the curves of anthropometric measures obtained in two national studies conducted among Iranian children and adolescents in 2003-2004 and 2...

I will use the terms “reference centiles” or “centile charts,” as the setting that I consider here is more general than that of “growth charts.” Longitudinal reference centiles over some measure of time (typically age) are almost always implemented repeatedly on the same individual. In this kind of setting the notion of conditional or adaptive centile charts is very appealing, particularly when...

1. Overview. Wei and He are to be congratulated on an innovative and important article. The conditional approach to growth charts described in their article is important in a practical sense, and the use of quantile regression is both natural and well motivated. We look forward to further application of their idea to actual practice, because the concept of “falling behind” in one’s growth cycle...

First, I would like to congratulate the authors for an interesting application of their semiparametric quantile regression model to longitudinal human growth data. On an earlier occasion, I had an opportunity to collaborate with the authors on applying this method for the purpose of constructing semilongitudinal growth charts for height and for body mass index. As my background is in medicine r...

Uncritical application of standard weight percentile charts, derived from white infants, to infants from different ethnic groups may result in an overestimate of the incidence of intrauterine growth retardation in those groups. The ratio of mid-arm circumference to occipitofrontal circumference was studied in 194 babies (49 Asian, 58 black, and 87 white). In contrast with birth weight the ratio...