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Updated: Mar 5, 2026
Assessment of Child Anthropometry in a Large Epidemiologic Study
Published on: February 2, 2017
Validity of anthropometric equations to estimate infant fat mass at birth and in early infancy
Jennifer S Cauble1, Mira Dewi1, Holly R Hull2
1Department of Dietetics and Nutrition, School of Health Professions, University of Kansas Medical Center, 3901 Rainbow BLVD, Mail Stop 4013, Kansas City, KS, 66160, USA.
Insights
Newborn fat mass estimation equations show poor accuracy and agreement with measured values at birth and 3 months. Validation is needed for reliable body composition assessment in infants.
Area of Science:
- Pediatrics
- Human Physiology
- Body Composition Analysis
Background:
- Existing newborn fat mass estimation equations lack sufficient validation for use at birth and during infancy.
- Current pediatric body composition assessment often uses equations developed for different age groups.
Purpose of the Study:
- To validate four common newborn fat mass estimation equations.
- Compare estimated fat mass against air displacement plethysmography (ADP) measurements at birth and 3 months.
Main Methods:
- Ninety-five newborns underwent body composition analysis using ADP (Pea Pod) and skinfold measurements.
- Sixty-three infants had repeat measurements at 3 months.
- Statistical analyses included paired t-tests, linear regression, R-squared, standard error of the estimate (SEE), and Bland-Altman plots.
Main Results:
- At birth, three of the four equations (Deierlein, Lingwood, Aris) showed significant differences compared to ADP measurements.
- At 3 months, all tested equations significantly differed from ADP measurements.
- Poor precision, accuracy, and bias were observed across most equations at both time points.
Conclusions:
- Newborn fat mass prediction equations demonstrate inadequate agreement, precision, and accuracy when compared to criterion measures.
- Clinical application of these equations for body composition assessment in newborns and infants requires caution due to poor validation.
Background:
In newborns and children, body fat estimation equations are often used at different ages than the age used to develop the equations. Limited validation studies exist for newborn body fat estimation equations at birth or later in infancy. The study purpose was to validate 4 newborn fat mass (FM) estimation equations in comparison to FM measured by air displacement plethysmography (ADP; the Pea Pod) at birth and 3 months.
Methods:
Ninety-five newborns (1-3 days) had their body composition measured by ADP and anthropometrics assessed by skinfolds. Sixty-three infants had repeat measures taken (3 months). FM measured by ADP was compared to FM from the skinfold estimation equations (Deierlein, Catalano, Lingwood, and Aris). Paired t-tests assessed mean differences, linear regression assessed accuracy, precision was assessed by R2 and standard error of the estimate (SEE), and bias was assessed by Bland-Altman plots.
Results:
At birth, FM measured by ADP differed from FM estimated by Deierlein, Lingwood and Aris equations, but did not differ from the Catalano equation. At 3 months, FM measured by ADP was different from all equations. At both time points, poor precision and accuracy was detected. Bias was detected in most all equations.
Conclusions:
Poor agreement, precision, and accuracy were found between prediction equations and the criterion at birth and 3 months.
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