Rate of change in body mass index at different ages during childhood and adult obesity risk

Background: Childhood body mass index (BMI) predicts adult obesity. How growth trajectories during childhood relate to adult obesity risk is not well defined. Objective: We aimed to characterize BMI growth trajectories from childhood to midlife and to examine the associations between BMI growth rates at childhood age points and adult obesity risk. Methods: The longitudinal study included 2732 participants with repeated BMI measurements from childhood (4-19 y) to adulthood (20-51 y). A random-effects model was used to construct BMI growth curves by race and sex. Model-estimated levels and linear growth rates of BMI were linked to adult obesity in separate multivariable logistic regression models at individual childhood age points. Results: BMI followed cubic growth curves. Childhood BMI linear slope estimates were higher in adults with obesity than in adults without obesity (P < 0.001). The association between childhood BMI growth rate and adult obesity was significantly higher in puberty and postpuberty (12-19 y) than in early childhood (4-11 y) with a peak at age 14 (odds ratio = 3.1 and 95% confidence interval, 2.7-3.5). Conclusions: Rates of change in BMI at different childhood ages are differentially associated with adult obesity. Puberty and postpuberty are crucial periods for the development of obesity in later life.