Body mass index trajectories during infancy and pediatric obesity at 6 years.

Purpose: The purpose of the article was to examine the relationship between body mass index (BMI) trajectories during infancy and risk of obesity at the age of 6 years.

Methods: We used data on 1169 children with at least two BMI measures during their first year of life from the Infant Feeding Practices Survey II and its Year 6 Follow-Up. Latent class growth analysis was used to identify distinct trajectories of BMI, and multiple logistic regression analyses were used to assess the association of the identified trajectories with obesity at the age of 6 years.

Results: Three trajectories of BMI were identified during the first year of life: low stable (80.2%), high stable (16.9%), and rising (2.8%). Obesity at the age of 6 years was highest among children with a high-stable trajectory (17.2%), followed by the low-stable (9.6%) and rising (9.1%) groups. Compared with those in the low-stable trajectory, the adjusted odds ratio for obesity at the age of 6 years was 1.79 (95% confidence interval 1.13-2.84) in children with the high-stable growth trajectory and 0.84 (0.26-2.72) in children with the rising growth trajectory.

Conclusions: High-stable BMI trajectory in infancy resulted in a higher risk for obesity at the age of 6 years, but had low accuracy for identifying obese children at the age of 6 years.