O3299: Can Preschool BMI Changes Flag Children at Highest Risk for Adolescent Obesity?

Background: Obesity is a leading barrier to military service in 17-24 year olds. Although 44% of military-connected youth express an intent for military service, they are not immune to the increasing prevalence of childhood obesity. Earlier diagnosis for those at risk for obesity in adolescence could prompt earlier intervention, improve health outcomes, and preserve the opportunity to pursue military service. The aim of this study was to characterize body mass index (BMI) trajectory during the preschool years of adolescents with normal weight, overweight, and obesity. We hypothesized that the combination of rate of change in preschool BMI percentile plus absolute BMI percentile at age 5-6 years would be a better predictor of adolescent obesity than early childhood BMI percentile alone.

Methods: Height and weight data from the Military Health System (MHS) Data Repository were evaluated for 4,941 children aged 12-15 years receiving care from a military treatment facility in 2019. We included records with at least 10 valid BMI measures between ages 2-6 years and at least 1 follow up BMI between ages 12-15 years. Exclusion criteria included genetic syndromes associated with obesity, chronic glucocorticoid use, and hypothalamic injury. Linear mixed effects models characterized BMI trajectories over the preschool years and multivariable logistic regression models estimated the association of BMI trajectory characteristics over the preschool years with obesity risk in adolescents. Logistic generalized additive models estimated associations of BMI trajectory characteristics with obesity risk in adolescence.

Results: Obesity prevalence was 8.6% at age 2-3 years, 8.9% at age 5-6 years, and 14.1% in adolescence. Of children with obesity at age 2-3 years, 41.6% had obesity in adolescence and 32.9% returned to a healthy weight. Of children with obesity at age 5-6 years, 69.9% had obesity in adolescence and 10.3% returned to a healthy weight. The mean annual change during the preschool years in BMI percent of the 95th percentile for all children was -1.21 (SD 2.08). Children with a BMI at age 5-6 years of ≥110% of the 95th percentile and a positive BMI percentile slope had ≥70% probability of obesity in adolescence. Children with a BMI at the upper end of the healthy range at ages 2-3 years and increasing BMI percentiles during the preschool years had ≥30% probability of obesity in adolescence.

Conclusion: Military connected youth at greatest risk for adolescent obesity had a combination of high BMI and BMI gain in their preschool years. Children with obesity at age 2-3 years were more likely to have obesity as adolescents than to return to a healthy weight. Risk predictions derived from this large, retrospective MHS cohort may contribute to a prognostic tool to prompt intervention to prevent future obesity, associated morbidity, and to preserve the health and readiness of military families.