The Moderating Role of Cortisol Reactivity on the Link Between Maltreatment and Body Mass Index Trajectory Across Adolescence.

Purpose: Child maltreatment increases risk for obesity, yet differential effects of maltreatment type remain unclear. Cortisol reactivity may help clarify these effects, given links among cortisol reactivity, maltreatment, and obesity. We examined these associations in boys and girls across adolescence.

Methods: We collected data from 454 adolescents (212 girls) across four waves (aged 8-13 years at Time 1), including 303 maltreated youth. We modeled body mass index (BMI) percentile trajectories arrayed by age separately for boys and girls and tested whether cortisol reactivity at Time 1 moderated the association between maltreatment type and BMI growth.

Results: In girls, cortisol reactivity moderated the association between maltreatment type and quadratic change in BMI. At low levels of cortisol, sexually abused girls had a steeper quadratic increase in BMI compared with comparison (-.65, 95% confidence interval [CI] -1.09 to -.22) and physically abused (-.76, 95% CI -1.29, -.24) girls. At high levels of cortisol, sexually abused girls did not differ from comparison (.15, 95% CI -.40 to .70) or physically abused (.21, 95% CI -.38 to .80) girls in quadratic change in BMI. In boys, cortisol reactivity did not moderate the association between maltreatment type and BMI growth.

Conclusions: The combination of lower cortisol reactivity and sexual abuse may put girls at risk for BMI increase during later adolescence. Given the negative consequences of high BMI, identifying and intervening with these girls could lead to better health and well-being among this group. Cortisol reactivity may not play the same role among boys.