Heterogeneity of sex-stratified BMI trajectories in children from 8 to 14Â years old

- Four BMI trajectories were found among 461 children between 8 and 14 years old.
- BMI developmental trajectories differed according to sex.
- In overweight and obese youths, BMI remained stable over time.
- Body dissatisfaction, media influence and victimization predicted group membership.

ObjectiveDescribe and predict sex-stratified trajectories of weight change in youths transitioning from childhood to adolescence.MethodsUsing an accelerated longitudinal design, 461 children between 8 and 12 years old at baseline were followed over three years. Body mass index was calculated from self-reported height and weight. Latent class growth analysis was used to identify BMI trajectories and multinomial logistic regressions, to predict group membership.ResultsA four-group heterogeneous trajectory model emerged for boys and girls alike. Characteristics of the trajectories differed between sexes and no obesity group was found for boys. Sociocultural factors, such as media influence, body dissatisfaction, weight victimization, awareness of thin-ideal standards and related pressures were important correlates of trajectory membership.ConclusionBMI trajectories during preadolescence are stable over time for heavier children. Body image concerns and weight stigmatization stand out as important factors in the prediction of developmental weight trajectories and could therefore be integrated in weight gain prevention programs for children of all weights as well as in weight management interventions for overweight and obese children.