Relationship between depressive symptoms and salivary awakening cortisol concentration in adolescents

Objective To investigate the association between depressive symptoms and early morning awakening salivary cortisol levels,and to provide reference for effectively controlling and preventing depressive symptoms among adolescents.Methods A total of 1 552 students in grade 3 to 5 from 3 primary schools in Ma'an shan were recruited.Saliva was collected immediately on awakening.Cortisol concentration was analyzed by using enzyme-linked immunosorbent assay(ELISA).Depressive symptoms were assessed by Mood and Feelings Questionnaire-Child version(MFQ-C).Body mass index was calculated after physical examination.A questionnaire survey was conducted by collecting information on physical activity,screen time,sleep duration,parental education,pubertal development,as well as household economic status.Logistic regression model was used to evaluate the association between the depressive symptoms and salivary awakening cortisol concentration in adolescents.Results Among all the 861 boys and 691 girls,the detection rate of depressive symptoms was 16.4%,the median cortisol concentration of depression group (374.38 ng/mL) was higher than that of non-depression group(339.42 ng/mL),with statistical significance(u=29.38,P<0.01).Compared to cortisol concentration in P25-P75 group,adolescents with cortisol level ≤ P25 group had lower rate of depressive symptoms(OR =0.52,95%CI=0.35-0.78),adolescents with cortisol level ≥P75 group had higher rate of depressive symptoms(OR =1.47,95%CI=1.07-2.01).Conclusion High concentration of awakening cortisol in adolescents is associated with higher risk of adolescent depressive symptoms among adolescents.