Context. Obesity and cardiometabolic diseases are associated with higher long-term glucocorticoid levels, measured as scalp hair cortisol (HairF) and cortisone (HairE). Cardiometabolic diseases have also been associated with copeptin, a stable surrogate marker for the arginine-vasopressin (AVP) system. Since AVP is, together with corticotropin-releasing hormone (CRH,) an important regulator of  the hypothalamic- pituitary adrenal axis (HPA-axis), we hypothesize that AVP contributes to chronic hypercortisolism in obesity.

Objective. To investigate whether copeptin levels are associated with higher HairF and HairE levels in obesity.

Design, setting and patients. A cross-sectional study in 51 adults with obesity (body mass index ≥30 kg/m²).

Methods. Associations and interactions between copeptin, HairF, HairE, and cardiometabolic parameters were cross-sectionally analyzed.

Results. Copeptin was strongly associated with body mass index (BMI) and waist circumference (WC), (rho=0.364 and 0.530, p=0.008 and <0.001 respectively), also after correction for confounders. There were no associations between copeptin and HairF or HairE on a continuous or dichotomized scale, despite correction for confounders.

Conclusion. In patients with obesity, AVP seems not a major contributor to the frequently observed high cortisol levels. Other factors which stimulate the HPA-axis or affect cortisol synthesis or breakdown may be more important than the influence of AVP on long-term glucocorticoid levels in obesity.