Body Mass Index Peak-Rebound Patterns and Inhibitory Control Among Young Children

Importance Childhood obesity has been linked with poor inhibitory control, and atypical body mass index (BMI) growth trajectories may identify children at higher risk for poor inhibitory control. Inhibitory control is also sexually dimorphic (male vs female), as maladaptive inhibitory control is more common in males. Objective To investigate the association between early childhood BMI peak-rebound patterns and inhibitory control development at 4 to 5 and 6 to 7 years and test whether there is a sexually dimorphic association. Design, Setting, and Participants The Programming Research in Obesity, Growth, Environment, and Social Stressors study is a prebirth cohort that recruited pregnant women receiving prenatal care through the Mexican Social Security Institute from July 2007 to February 2010 and followed up from pregnancy through age 8 years. Data were analyzed from November 2024 to December 2025. Exposure Repeated weight and length or height measurements were collected from birth to 8 years and mixed-effects models were used to characterize sex- and child-specific BMI trajectories and derive age and magnitude of the BMI peak (maximum inflection point during infancy) and rebound (minimum inflection point during early childhood). Main Outcomes and Measures Children completed the Conners Kiddie Continuous Performance Test, second edition, to assess inhibitory control at ages 4 to 5 and 6 to 7 years, and linear mixed-effects models were used to assess associations of age and magnitude of BMI peak and rebound with inhibitory control across the 2 time points. Sex-specific trajectories were evaluated by modeling interactions between child sex. Results Among 539 children included in the study, 278 (51.6%) were male; 277 (51.4%) were born to mothers with low socioeconomic status, and the mean (SD) gestational age at birth was 38.4 (1.6) weeks. After adjusting for covariates, a 1-SD higher BMI at peak was associated with higher T-scores for hit reaction time standard errors (β = 0.89; 95% CI, 0.20 to 1.58). A 1-SD higher age at rebound was associated with higher hit reaction time (β = 2.35; 95% CI, −0.01 to 4.72). However, age at peak and BMI at rebound were not associated with any inhibitory control measure. Children with early timing of peak and rebound exhibited higher T-scores for omission errors (β = 4.05; 95% CI, 0.96 to 7.13), while children with early timing of peak and late timing of BMI rebound had lower T-scores for hit reaction time (β = −4.16; 95% CI, −7.29 to −1.02) compared with those with normal timing of peak and rebound. In males, both older age and a higher magnitude of BMI rebound were associated with lower omission error T-scores, whereas in females, variations in age and magnitude of BMI patterns were associated with higher T-scores for hit reaction time and hit reaction time standard errors. Conclusions and Relevance In this cohort study of 539 children in Mexico, early-life BMI peak-rebound trajectories across childhood were associated with inhibitory control. These findings extend the literature beyond the well-established effects of BMI peak-rebound on metabolic conditions.