BMI changes during adolescence: Comparing maltreated adolescents by maltreatment type to a comparison sample

Introduction: Adult obesity is related to adolescent maltreatment. The objective of this study was to examine whether adolescents (n=301) with a particular maltreatment type (physical abuse, emotional abuse, neglect, or sexual abuse) have different BMI growth trajectories than adolescents with other types of maltreatment or comparison youth (n=151). Methods: Individual growth models via the SAS/MIXED procedure were used to estimate average growth trajectories of BMI scores, across adolescence (9 to 18 yrs). Both unconditional growth model and conditional linear and quadratic growth models with the time-invariant demographic covariates and the time-varying psychological/physical covariates were employed. The interaction of the covariates by linear or quadratic effect was removed if not significant. Results: There was both a significant linear and quadratic effect for the sexually abused group versus other maltreatment group and comparison group. The results indicated that the sexually abused group had slower BMI growth in early to mid-adolescence with a late adolescent steeper growth. The other maltreated and comparison groups (whose trajectories were not different) showed an increase in BMI in early to mid-adolescence which then declines in late adolescence. Discussion: The steep increase in BMI during late adolescence in sexually-abused youth may be an adaptive mechanism to protect against sexual advances. There may be differential responses by maltreatment type to psychobiological conditions related to obesity seen in abused adolescents, such as hypersecretion of cortisol. Close monitoring of weight gain in sexually-abused adolescents is needed to allow for psychological and educational interventions to prevent obesity.