ESPE Abstracts

Background: Close monitoring of growth is vital when following children with achondroplasia yet existing growth curves suffer from a simple chart format and their clinical use is therefore limited. Also, references for body proportions; i.e. sitting height, relative sitting height and arm span, are lacking.

Objective and hypotheses: The aim of this study was to construct age-specific growth curves for height, weight, body mass index, head circumference and body proportions in children with achondroplasia.

Method: A combination of longitudinal and cross-sectional measurements were collected from about 550 children and adolescents with achondroplasia aged 0 to 20 years. Standard deviation curves were estimated using the Generalized Additive Models for Location, Scale and Shape (GAMLSS).

Results: Retrieved averages for these four variables were similar to the existing growth references by Horton et al. and Hoover-Fong et al. To better capture growth development during the first 4 years of life, the curves for head circumference, height and weight were combined on the same page by using logarithms for all axes. Similar approaches were used for the design of a separate BMI and a separate head circumference chart, both covering 0–20 years of age.

Conclusion: Sex- and age-specific curves for height, weight, body mass index and head circumference were constructed and designed in a format that makes it easy to follow growth development of the individual. The body proportion references are under construction.

Funding information: This work was supported by Stiftelsen Promobilia.