Hypothalamic-pituitary-adrenal axis and smoking and drinking onset among adolescents: the longitudinal cohort TRacking Adolescents' Individual Lives Survey (TRAILS)
Aims. We examined within a prospective longitudinal study whether cortisol levels were associated with smoking or drinking behaviors, taking parental substance use into account.
Design The influence of parental substance use on cortisol levels of their adolescent offspring at age 10-12 was examined. Next, cortisol levels of adolescents who initiated smoking or drinking at the first data collection (age 10-12) were compared to non-users. Finally, we examined whether cortisol levels could predict new onset and frequency of smoking and drinking two years later. Setting and participants. First and second assessment data of the TRacking Adolescents’ Individual Lives Survey (TRAILS) were used, including 1,768 Dutch adolescents aged 10-12 years, who were followed up across a period of two years. Measurements. Cortisol was measured in saliva samples at awakening, 30 minutes later, and at 8 p.m. at age 10-12. Self-reported substance use at age 10-12 and 13-14, and parental self-reported substance use were used. Findings. Only maternal substance use was related to slightly lower adolescent cortisol levels at 8 p.m. Both maternal and paternal substance use were associated with adolescent smoking and drinking at age 13-14, although fathers’ use only predicted the amount used and not the chance of ever use. Finally, higher cortisol levels were moderately related to current smoking and future frequency of smoking, but not to alcohol use. Conclusions. In a general population, parental heavy substance use does not seem to consistently affect cortisol levels in their offspring. We found some evidence for higher, instead of lower, HPA axis activity as a predictor of smoking in early adolescence.