ESPE Abstracts

Background and Objectives: Childhood obesity is a global public health threat, with an alarming rise in incidence. Obesity at young age has short-term consequences, as well as long-term morbidity. It is, therefore, important to determine body composition longitudinal throughout infancy and childhood to prevent excess adiposity. Multiple methods are used to determine body composition in infants and young children, but none are described as suitable for longitudinal use in infancy and throughout childhood. Our research group has published sex-specific reference values for measurements with ADP and DXA with vacuum cushion to prevent movement artifacts, for infants aged 1 month – 2 years, but not yet for older ages. Our primary objective was to construct sex-specific body composition reference values for children aged 2-5 years using DXA, which could be longitudinally used in clinical practice and research.

Methods: In the Sophia Pluto cohort, longitudinal DXA-measurements were performed in 340 term-born children aged 2 – 5 years, using Lunar Prodigy with Encore software (V14.1). Using LMS-method, sex-specific reference values were created for fat mass (FM), fat mass percentage (FM%) and fat free mass (FFM). Bland- Altman analysis was used to determine if DXA measurements with vacuum cushion, performed in 0-2 year old infants in our cohort, were comparable with DXA measurements without vacuum cushion after age 2 years. A random sample of 2 year old children was measured in duplicate.

Results: Sex-specific body composition values for age 2-5 years were constructed. In boys and girls, FM and FFM increased from 2-5 years and FM% decreased. Girls had higher FM and FM% and lower FFM compared to boys. Absolute measurements FM, FM% and FFM were different between DXA with and without vacuum cushion, with mean difference [limits-of-agreement(LOA)] of 1.86 kg [1.39;2.33], 13.75% [9.56;17.94] and -1.54kg[-1.99;-1.09], resp., there was a fixed bias, no proportional bias. At age 2 years, the SD-scores based on the existing reference values for 1 month-2 years (with cushion) and for present references for 2-5 years (without cushion) were comparable.

Conclusions: We constructed sex-specific reference values for fat mass, fat mass percentage and fat free mass measured by DXA for children aged 2-5 years. These reference values can be used longitudinally in children aged 1 month to 5 years, because the SD-scores were comparable with existing reference values for children aged 0-2 years.