Association Between maternal body mass index, offspring growth and pubertal timing: results from a longitudinal birth cohort study

Earlier pubertal timing has risen alongside increasing childhood obesity, yet evidence linking early-life body mass index (BMI) to earlier pubertal timing, particularly for boys, remains inconsistent. Prior work often relied on single time-point BMI measurements that overlooked growth dynamics and the potential independent effect of maternal pre-pregnancy BMI. Using data from 2982 participants in the Amsterdam Born Children and their Development cohort, we linked pubertal timing ages 11-12 to maternal BMI and children's dynamic BMI growth curves from birth to age 8. Joint Bayesian models of linear mixed-effects and ordinal logistic regressions, stratified by sex and adjusted for confounders, found that greater BMI deviations from population curves, during infancy and prepuberty, were associated with earlier pubertal timing in girls (infancy POR: 1.11, 95% CI: 1.02-1.20; prepuberty POR: 1.23, 95% CI: 1.12-1.38) and boys (infancy POR: 1.12, 95% CI: 1.03-1.22; prepuberty POR: 1.23, 95% CI: 1.08-1.42), with preschool additionally important for girls (POR: 1.55, 95% CI: 1.22-1.99). Independent of child BMI growth deviations, higher maternal pre-pregnancy BMI was associated with earlier pubertal timing in girls (POR: 1.07, 95% CI: 1.05-1.11) and boys (POR: 1.08, 95% CI: 1.05-1.11). To conclude, findings highlight intergenerational associations and the value of early growth.