Pre-, Perinatal, and Parental Predictors of Body Mass Index Trajectory Milestones

Objective To assess associations of pre-, perinatal, and parental factors with age and magnitude at body mass index (BMI) peak and rebound. Study design Among 1681 children with BMI data from birth to mid-childhood in Project Viva, we fitted individual BMI trajectories using mixed-effect models with natural cubic spline functions and estimated age and magnitude at peak in infancy and rebound in early childhood. We used stepwise multivariable regression to identify predictors of peak and rebound in the 1354 (63.6%) children with estimable trajectory milestones. Results The mean (SD) of age at BMI peak was 8.4 (2.7) months and at rebound was 59.8 (19.6) months. and the mean (SD) of magnitude at peak was 18.0 (1.4) kg/m(2) and at rebound was 15.9 (1.2) kg/m(2). Girls had a later age at peak, earlier age at rebound, and lower magnitudes at peak and rebound than boys. Maternal isolated hyperglycemia (vs normoglycemia: 11 0.7 months [95% CI 0.2-1.2]) and pre-eclampsia (vs normal blood pressure: 1.6 months [0.8-2.4]) were associated with a later peak, and impaired glucose tolerance (vs normoglycemia: -0.5 kg/m 2 [-0.9, -0.1]) was associated with a lower magnitude at peak. Greater maternal first-trimester weight gain, smoking during pregnancy, no breastfeeding, parental obesity, and no university education were associated with greater BMI at rebound. Conclusions We have identified modifiable prenatal and parental predictors of BMI peak in infancy and rebound in childhood. Early-life interventions that address these factors may be effective in changing BMI peak and rebound and potentially preventing later obesity.