Related Experiment Video
Updated: Apr 21, 2026
Scanning Skeletal Remains for Bone Mineral Density in Forensic Contexts
Published on: January 29, 2018
Bias related to body mass index in pediatric echocardiographic Z scores
Frederic Dallaire1, Jean-Luc Bigras, Milan Prsa
1Division of Pediatric Cardiology, Department of Pediatrics, Faculty of Medicine, University of Sherbrooke, 3001, 12e Avenue Nord, Sherbrooke, QC, J1H 5N4, Canada, frederic.a.dallaire@usherbrooke.ca.
Insights
Pediatric cardiac Z scores can be biased by body mass index (BMI). Multivariable models using height and weight reduce this bias, improving accuracy in echocardiography for children.
Area of Science:
- Pediatric Cardiology
- Medical Imaging
- Biostatistics
Background:
- Cardiac dimensions in pediatric echocardiography are typically normalized using weight, height, or body surface area (BSA).
- The relationship between body size metrics like body mass index (BMI) and cardiac dimensions is complex and age-dependent.
- Existing normalization methods may not adequately account for the influence of BMI on cardiac size in children.
Purpose of the Study:
- To investigate if bivariate normalization models for proximal aorta diameter Z scores introduce BMI-related bias in children.
- To determine if multivariable models can reduce or eliminate this BMI-related bias.
- To compare the effectiveness of different regression models in pediatric echocardiography normalization.
Main Methods:
- Analysis of 1,422 normal pediatric echocardiograms (children ≤18 years).
- Calculation of proximal aorta diameter Z scores using allometric, polynomial, and multivariable regression models.
- Assessment of residual association between Z scores and age/sex-adjusted BMI.
Main Results:
- Significant residual linear association between BMI-for-age and Z scores was found in children ≥6 years for most bivariate models.
- Only a multivariable model incorporating both weight and height as independent predictors yielded Z scores free of BMI association.
- Bivariate normalization models, irrespective of the normalizing variable, introduced BMI-related bias in proximal aorta Z scores.
Conclusions:
- Bivariate normalization methods for pediatric proximal aorta diameter Z scores are susceptible to BMI-related bias.
- Multivariable models, specifically those including weight and height, are recommended to mitigate this bias.
- Exploring multivariable approaches is crucial for refining pediatric echocardiography reference values and improving diagnostic accuracy.
Abstract:
In pediatric echocardiography, cardiac dimensions are often normalized for weight, height, or body surface area (BSA). The combined influence of height and weight on cardiac size is complex and likely varies with age. We hypothesized that increasing weight for height, as represented by body mass index (BMI) adjusted for age, is poorly accounted for in Z scores normalized for weight, height, or BSA. We aimed to evaluate whether a bias related to BMI was introduced when proximal aorta diameter Z scores are derived from bivariate models (only one normalizing variable), and whether such a bias was reduced when multivariable models are used. We analyzed 1,422 echocardiograms read as normal in children ≤18 years. We computed Z scores of the proximal aorta using allometric, polynomial, and multivariable models with four body size variables. We then assessed the level of residual association of Z scores and BMI adjusted for age and sex. In children ≥6 years, we found a significant residual linear association with BMI-for-age and Z scores for most regression models. Only a multivariable model including weight and height as independent predictors produced a Z score free of linear association with BMI. We concluded that a bias related to BMI was present in Z scores of proximal aorta diameter when normalization was done using bivariate models, regardless of the regression model or the normalizing variable. The use of multivariable models with weight and height as independent predictors should be explored to reduce this potential pitfall when pediatric echocardiography reference values are evaluated.
More Related Videos
04:05Author Spotlight: Unveiling Prognostic Indicators in Heart Failure - The Role of Phase Angle and Bioelectrical Impedance Analysis
Published on: June 30, 2023
09:31Hemodynamic Precision in the Neonatal Intensive Care Unit using Targeted Neonatal Echocardiography
Published on: January 27, 2023
Related Concept Videos
01:17z Scores and Area Under the Curve
01:05Introduction to z Scores
z scores...
01:06Introduction to z Scores
z scores...
01:07z Scores and Unusual Values
This score indicates how far a value is from the mean in terms of standard deviation. For example, if a data value has a z score of +1, the researcher can infer that the particular data value is one standard deviation above the mean. If another data...