Birth outcomes, early growth patterns and age at adiposity rebound: evidence from the Ma’anshan birth cohort (MABC) study

Abstract Objective: The age at AR (adiposity rebound) in humans appears to be earlier. Increasing studies found that early age at AR (EAR) are associated with subsequent obesity and related complications, but it is unclear whether birth outcomes and early growth patterns are important factors in AR. We aimed to investigate the effect of birth outcomes and early growth patterns in the first two years on the timing of AR.Methods: A prospective cohort study of 2705 children was included in this study. Early growth levels were calculated based on BMI and head circumference in the first two years. We defined the criteria for rapid weight gain (RWG) in infancy as a change in weight SD score > +0.67 from birth to 12/18/24 months. Group-based trajectory modeling (GBTM) and fractional polynomial function models were used to determine body mass index (BMI) trajectory from birth to 24 months and estimate children’s age at AR, respectively. Binary logistic regression models and multivariate linear regression models were used.Results: Children born with small size (SGA, LBW, and smaller length, weight and head circumference) and short gestational age (GA) (PTB and shorter GA) were associated with EAR. Children with RWG was associated with an increased risk of EAR. Children’s BMI and head circumference were negatively associated with age at AR before 12 months, but this association changed radically afterwards. Furthermore, children with rising BMI trajectory and low BMI trajectory in the first two years were both associated with an increased risk of EAR compared to medium BMI trajectory.Conclusions: Both birth outcomes and early growth patterns will influence subsequent age at AR.