Clinical and biological correlates of morning serum cortisol in children and adolescents with overweight and obesity

BACKGROUND AND AIM: A fraction of children with obesity have increased serum cortisol levels. In this study, we describe the clinical characteristics of obese children and adolescents with elevated morning serum cortisol levels and the relationship between the cortisol levels and components of the metabolic syndrome. METHODS: Retrospective medical record review study of children aged 4 to 18 years with overweight or obesity seen for obesity management in the Pediatric Obesity Clinic of the UZ Brussel between 2013 and 2015. RESULTS: A total of 234 children (99 boys and 135 girls) with overweight (BMI z-score > 1.3) without underlying endocrine or genetic conditions were included. Mean (SD) age was 10.1 (2.8) years, BMI SD-score 2.5 (0.6), and body fat percentage 37% (7.9). Serum fasting cortisol levels were elevated (>180 μg/L) in 49 children, normal (62–180 μg/L) in 168, and decreased (<62 μg/L) in 12. Serum fasting cortisol was not significantly correlated with gender, age, or degree of adiposity. But correlated significantly with fasting glucose (R(s) = 0.193; p < 0.005), triglycerides (R(s) = 0. 143; p < 0.05), fibrinogen (R(s) = 0.144; p < 0.05) and leptin levels (R(s) = 0.145; p < 0.05). After adjustment for serum insulin and leptin, the correlation between serum cortisol and fasting glucose remained significant. CONCLUSION: Elevated morning serum cortisol levels were found in 20% of overweight or obese children and adolescents, irrespective of the degree of adiposity, and were associated with higher fasting glucose, irrespective of underlying insulin resistance. The long-term cardiometabolic consequences of hypercortisolemia in childhood obesity needs further study.