Substance Use and Obesity Trajectories in African Americans Entering Adulthood

Introduction: The transition to adulthood can be stressful for minority adolescents, and many may cope through unhealthy behaviors, including substance use and obesity-related behaviors. This study tested substance use and obesity trajectories over time in African American youth, longitudinal associations of trajectories with mental and physical health in adulthood, and whether self-control and sex predict trajectories. Methods: Two longitudinal studies of 516 and 992 African American adolescents. In Study 1, substance use and obesity trajectories were assessed from ages 19 to 25 years. At age 25 years, internalizing and externalizing problems, metabolic syndrome, and inflammatory biomarkers were measured. In Study 2, substance use and obesity trajectories were assessed from ages 17 to 29 years. Depression, delinquency, diabetes, blood pressure, and inflammatory biomarkers were measured at age 29 years. Data analyses were conducted in 2017. Results: Across both studies, the majority of African American adolescents evinced poor health behavior trajectories (latent class growth analyses), with 23%–27% showing increasing substance use over time, 18%–27% showing increasing obesity over time, and 9%–11% showing increases in both. ANCOVAs for trajectory analyses revealed that males were more likely to evince increasing substance use, with females more likely to show increasing obesity. Substance use trajectories were associated with poorer mental health in adulthood; obesity trajectories with poorer physical health in adulthood. Those with good health behavior trajectories had higher self-control in early adolescence. Conclusions: The transition to adulthood is a vulnerable period for many African Americans. Given the commonalities of substance use and obesity in their rewarding/stress-relieving properties, similar prevention efforts may help stem the rise of both in these youth.