Increased cortisol reactivity may play a mechanistic role in predicting weight gain among adolescent girls, suggesting teens exposed to prenatal drug use are at particularly high risk for overweight or obesity due to a blunted stress response, according to findings published in Pediatric Obesity.

“Stressors, such as prenatal drug exposure (cocaine/heroin), may impact fetal brain development and dysregulate the [hypothalamic-pituitary-adrenal] axis and the cortisol response to stress,” Maureen M. Black, PhD, the John A. Scholl, MD and Mary Louise Scholl, MD professor of pediatrics at the University of Maryland School of Medicine, and colleagues wrote in the study background. “It is plausible that repeated activation of cortisol secretion leading to disruption of the neuroendocrine system in response to stressors, such as [prenatal drug exposure], may have detrimental effects on metabolic processes related to appetite and weight gain.”

Black and colleagues analyzed data from 76 black adolescents (mean age, 14 years; 50% boys) exposed to prenatal use of cocaine and heroin enrolled in a home-based trial for women with substance use disorder and their infants, as well as 61 children not exposed to prenatal use of cocaine or heroin recruited from a primary care clinic (controls). All adolescents participated in a lab-based assessment (time 1) and a 1-year follow-up (time 2). At time 1, adolescents completed several neuropsychological assessments, including the Conners’ Continuous Performance Test, and provided saliva samples collected during a 4.5- to 6-hour period (collected after a 3-hour fast), later assayed for cortisol. The first saliva sample was collected before completing computer-based tasks considered to be mild stressors that measured risk-taking propensity; a second sample was collected post-task. BMI z score was measured at baseline and follow-up. Researchers performed a bootstrapped moderated mediation analysis to test for conditional, indirect effects of cortisol reactivity.

Within the cohort, 18% had overweight and 27% had obesity.

Researchers found that lower inhibition was associated with increased cortisol reactivity in adolescents not exposed to prenatal drug use, and increased cortisol reactivity was associated with weight gain in girls only. Cortisol reactivity mediated the relationship between inhibition and BMI z score change for girls in the control group. Further, an examination of the index of moderated mediation showed that indirect effects were different for girls in the control group vs. those exposed prenatally to drugs (–0.006; 95% CI, –0.0136 to –0.0005).

“Results of the current study highlight the role of biological underpinnings in the relation between inhibition and weight gain,” the researchers wrote. “Results show that physiological processes likely play a mechanistic role. Interventions that target self-regulation skills have produced improvements in executive functioning and weight regulation, and cortisol reactivity may be a biomarker for targeted interventions to improve biological regulation and, ultimately, health risk.” – by Regina Schaffer