Limitations of growth charts derived from longitudinal studies: the Euro-Growth Study

Length and weight for age (1-12 months) charts are presented for the longitudinal Euro-Growth Study. "Weight-for-length", another widely used growth chart, presents a problem from a methodological point of view. Target length values (53-77 cm) are not observed in all infants, leading to truncated age distributions at most target lengths. It was demonstrated that the age at which the target length was reached (Fig. 8) had a significant influence on weight especially at a smaller length. This implies that the weight-for-length charts are biased. This phenomenon is due to the longitudinal measurement schedule at prechosen ages and not at prechosen lengths, which is impossible. To obtain the desired length-corrected weight standards, it is advocated to construct age-related body mass indices.