Related Experiment Video
Updated: Aug 14, 2025
Assessment of Child Anthropometry in a Large Epidemiologic Study
Published on: February 2, 2017
Body mass index is not suitable for assessing body composition in children with spastic cerebral palsy
Laura M Breij1, Rick A H van de Ven2, Raquel Y Hulst3
1Rehabilitation Centre 'De Hoogstraat', Utrecht, Netherlands.
Insights
Body mass index (BMI) is not a reliable indicator of body fat percentage in children with spastic Cerebral Palsy (CP). This study found weak correlations and poor agreement between BMI and fat mass, especially in children with a BMI below 20 kg/m².
Area of Science:
- Pediatric Rehabilitation
- Body Composition Analysis
- Neuromuscular Disorders
Background:
- Accurate body composition assessment is crucial for managing children with spastic Cerebral Palsy (CP).
- Traditional metrics like Body Mass Index (BMI) may not accurately reflect fat mass in this population due to unique physiological characteristics.
- Bioelectrical Impedance Analysis (BIA) offers a potential alternative for measuring fat mass percentage.
Purpose of the Study:
- To evaluate the correlation and agreement between Body Mass Index (BMI) and fat mass percentage measured by Bioelectrical Impedance Analysis (BIA) in children with spastic Cerebral Palsy.
- To determine if BMI is a suitable proxy for fat mass in this specific pediatric population.
Main Methods:
- One hundred and three children with spastic CP (mean age 9 years) participated.
- Body composition was assessed using Bioelectrical Impedance Analysis (BIA) for fat mass percentage and calculated BMI from height and weight.
- Statistical analyses included Pearson's correlation coefficient and weighted Cohen's kappa coefficient for agreement.
Main Results:
- A weak correlation was observed between BMI and fat mass percentage, particularly in children with a BMI below 20 kg/m².
- Little agreement (kappa = 0.299) was found between the categorization of body composition based on BMI versus fat mass percentage.
- Significant inter-subject variability in fat mass percentage was noted.
Conclusions:
- Body Mass Index (BMI) is not a suitable measure for assessing fat mass in children with spastic Cerebral Palsy.
- Utilizing BMI instead of fat mass percentage increases the risk of misclassifying body composition in these children.
- Children with a BMI < 20 kg/m² are particularly vulnerable to misclassification of their body composition.
Purpose:
To measure body composition by using bioelectrical impedance analysis (BIA) and body mass index (BMI) and to investigate the correlation and agreement between BMI and fat mass percentage in children with spastic Cerebral Palsy.
Materials And Methods:
BIA was used to assess fat mass percentage and BMI was determined from body weight and height. BMI and fat mass percentage were both categorized into five categories. The association between fat mass percentage and BMI was assessed using Pearson's correlation coefficient. Agreement between BMI and fat mass percentage was investigated with weighted Cohen's kappa coefficient.
Results:
One hundred and three children with CP across all Gross Motor Function Classification Levels (61% boys, mean age 9 years) were included. Mean BMI was 18.3 kg/m2 and mean fat mass was 24.9%. A large inter-subject variability was found with a weak correlation between BMI and fat mass percentage in children with a BMI < 20 kg/m2. Little agreement (k = 0.299, CI 0.16-0.44) between the categorization of children based on BMI and based on fat mass percentage was found.
Interpretation:
The large inter-subject variability in fat mass percentage combined with little agreement between the BMI and BIA categories suggests that BMI is not a suitable measure of fat mass in children with CP.IMPLICATIONS FOR REHABILITATIONUsing body mass index (BMI) and instead of fat mass percentage increases the risk of misclassifying body composition in children with spastic Cerebral Palsy.Children with a BMI < 20 kg/m2 are more at risk to be misclassified for body composition.
