Exploring Categorical Body Mass Index Trajectories in Elementary School Children

Area of Science:

• Pediatric Health
• Obesity Research
• Life-Course Epidemiology

Background:

• Limited research exists on body mass index (BMI) trajectories specifically within elementary school children (grades K-5).
• Existing studies often focus on transitions from childhood to adolescence or adulthood.
• This study addresses the gap by examining BMI changes in early childhood.

Purpose of the Study:

• To explore changes in obesity status among elementary school children.
• To analyze body mass index (BMI) trajectories using life-course event methods.
• To identify patterns and predictors of BMI status changes in early childhood.

Main Methods:

• Utilized annual height and weight data from 414 kindergarten and first-grade students (2008-2013).
• Calculated sequences of a 4-state BMI variable (underweight, normal, overweight, obese).
• Employed TraMineR software for sequence analysis, including state distributions, transition rates, and cluster analysis.

Main Results:

• Identified 4 clusters (normal, stepped, mixed, obese) and 3 clusters (obese cases aggregated into stepped).
• Cluster membership was associated with ethnicity and socioeconomic status (SES).
• Observed significant variations in transition rates among BMI states across different clusters.

Conclusions:

• Stable obesity states emerge early in childhood, particularly in Hispanic children.
• Early identification and intervention are crucial for managing childhood obesity.
• Socioeconomic status and ethnicity are significant factors influencing BMI trajectories in young children.