Objective: To study the changes in serum cortisol levels in adolescents with type 1 diabetes (T1DM) and elevated depressive symptoms.
Methods: Twenty-eight adolescents with T1DM and 31 healthy peers were assessed for depressive symptoms using a depression self-rating scale developed by the Epidemiological Survey Center. Selected subjects were classified into four groups: T1DM with elevated depressive symptoms group (n=15), T1DM without elevated depressive symptoms group (n=13), elevated depressive symptoms without T1DM group (n=15), and normal control group (n=16). Fasting blood samples were collected in the morning, and the levels of serum cortisol were compared among the four groups. The correlations of serum levels of cortisol and glycosylated hemoglobin A1c (HbA1c) with the score of depression self-rating scale were evaluated by Pearson correlation analysis.
Results: The fasting serum cortisol levels in the 28 T1DM patients were significantly higher than in the 31 healthy peers (P<0.01). The fasting cortisol levels in the T1DM with elevated depressive symptoms group were significantly higher compared with those in the elevated depressive symptoms without T1DM group and normal control group (P<0.01). In adolescents with T1DM, serum HbA1c level was positively correlated with the score of depression self-rating scale (r=0.481, P=0.010).
Conclusions: The fasting serum cortisol levels in adolescents with T1DM and elevated depressive symptoms are significantly increased, suggesting that the patients with comorbidity of T1DM and depression develop dysfunction of the corticotropin-releasing hormone-adrenocorticotropic hormone-cortisol axis. The elevated depressive symptoms may be associated with a poor control of glucose metabolism.