ESPE Abstracts

Background: The hypothalamic–pituitary–adrenal (HPA) axis, and cortisol in particular, has been reported to be involved in obesity-associated metabolic disturbances in adults and in specific populations of adolescents.

Objective and hypotheses: To investigate the associations between serum ACTH and cortisol levels and cardiovascular risk factors in obese children and adolescents.

Method: Of 1119 obese children and adolescents ACTH at 0800 h, cortisol at both 0800 h and 1600 h, cardiovascular risk factors and insulin resistance were evaluated. All analyses were adjusted for possible confounding factors, and odds ratios were determined.

Results: ACTH was positively associated with fasting insulin and HOMA-IR but negatively with blood pressure, while cortisol was positively associated with systolic and diastolic blood pressure. Also, cortisol but not ACTH was positively associated with LDL. The diurnal cortisol rhythm, the ratio of cortisol at 0800 h/cortisol at 1600 h, was positively associated with ACTH. After adjustment for possible confounding factors, ACTH levels were significantly higher in subjects with HOMA-IR>3 but lower in subjects with hypertension, and higher cortisol levels were found in subjects with high blood pressure (≥95th percentile), hyperglycemia and high LDL-cholesterol (≥95th percentile). However, the ratio of cortisol at 0800 h/cortisol at 16 h was significantly higher in subjects only with HOMA-IR>3.

Conclusion: In obese children and adolescents, high morning ACTH levels are only positively associated with HOMA-IR while high cortisol levels are associated with hypertension, hyperglycemia and high LDL-cholesterol although within the normal range The flatter diurnal cortisol rhythm may be a feedback of insulin resistance. These specific relationships suggest complex mechanisms through which the HPA axis may contribute to metabolic impairments in obesity, and the interaction of between ACTH and the diurnal cortisol rhythm in the metabolic disorder merits further investigations.