Body fatness charts based on BMI and waist circumference

Area of Science:

• Public Health
• Anthropometry
• Obesity Research

Background:

• Current public health guidelines for obesity often rely on body mass index (BMI) alone.
• Assessing body fat percentage (PBF) is crucial for a comprehensive understanding of obesity and related health risks.
• Existing methods for estimating PBF can be complex or less accessible in clinical settings.

Purpose of the Study:

• To develop and present novel percent body fat (PBF) charts.
• These charts utilize body mass index (BMI) and waist circumference (WC) to supplement existing obesity guidelines.
• The aim is to provide a more intuitive tool for assessing fatness levels.

Main Methods:

• A semi-parametric spline approach was employed using data from the National Health and Nutrition Examination Survey (NHANES) III (18-65 years).
• The analysis graphically depicted the relationship between BMI, waist circumference (WC), and PBF without assuming specific functional forms.
• Four distinct PBF charts were generated, stratified by gender and ethnicity, using data from 7,712 participants.

Main Results:

• The semi-parametric spline model for PBF prediction demonstrated superior performance compared to linear models.
• For males, waist circumference (WC) emerged as the primary determinant of PBF, with BMI having minimal impact.
• In females, a more complex interplay between BMI and WC was observed, necessitating careful monitoring of both metrics for low body fat.

Conclusions:

• Proposed PBF charts offer a three-dimensional assessment of fatness, integrating BMI and WC.
• These charts are designed for ease of interpretation, comparable to standard BMI charts.
• The charts serve as a valuable supplement to current public health strategies for obesity assessment and management.