Early Childhood Growth Trajectories in a Medicaid Population

Background: Evidence on the role of early growth trajectories and later obesity risk is primarily based on privately insured or universally insured samples.

Objectives: We aimed to characterize and determine factors associated with early growth trajectories and estimate associations with overweight/obesity risk in a Medicaid-insured and uninsured cohort.

Methods: Infants seen at a large pediatric academic centre in 2010-2016 were included. Weight and length/height measurements were converted to age and sex-specific BMI z-scores (BMIz) based on the World Health Organization (WHO) Growth Standards. Group-based trajectories were modelled using BMIz created groups. Logistic and log-binomial regression models estimated associations between membership in trajectories and maternal/child factors and overweight or obesity at 36, 48, and 60 months, separately. Analyses were performed between 2019 and 2021.

Results: The best-fitting model identified five BMIz trajectories among 30 189 children and 310 113 clinical encounters; two trajectories showed rapid rise in BMIz. Lower maternal education, pre-pregnancy maternal overweight/obese status, and maternal smoking were positively associated with both rapid-rising BMIz trajectories. Children in either of the two rapid-rising trajectories were 3.00 (95% CI: 2.85, 3.25), 2.97 (95% CI: 2.77, 3.18) and 2.76 (95% CI: 2.53, 3.01) times more likely to have overweight or obesity at 36, 48, and 60 months, respectively compared to children in the stable trajectory groups.

Conclusions: Among Medicaid insured and uninsured children, several maternal and child characteristics were associated with early rapid-rise in BMIz. Clinical monitoring of early rapidly rising BMI may be important to address modifiable risk factors for obesity in families from low-income households.