The Absence of Cortisol Awakening Response Is Associated With Personality Traits in Bariatric Women

Abstract

Abstract Background: There is a large body of evidence linking obesity to the HPA axis and cortisol secretion or metabolism. Early work hypothesized that obesity onset may be associated with over-activation of the HPA axis, causing an extenuation of the system. The cortisol awakening response (CAR) has been suggested to be a reliable marker of HPA axis activity and has already been examined in samples of individuals with obesity. Our objective was to compare individuals showing a morning cortisol peak (CAR responders) from those who did not (non-responders) and identify possible metabolic or psychological differences among these two groups. Our hypothesis was that the two groups differed in the level of anxiety and aspects of their personality rather than in their metabolic profile. Methods: CAR response was determined using a baseline to peak cut-off of 2.5 nM. Nine CAR non-responder women awaiting bariatric surgery (BMI: 50.8 ± 4.6 kg/m2) were compared to 9 sex- and age-matched CAR responders (BMI: 48.1 ± 5.9 kg/m2). Participants collected salivary cortisol upon awakening as well as 15, 30 minutes after and responded to psychological questionnaires that measured anxiety (State and trait anxiety inventory questionnaire) and personality traits (Temperament and character inventory). Results: Non-responders were all non-diabetic women aged 37 ± 8 years. There was no significant difference between CAR responders and non-responders in terms of BMI or waist circumference. No difference was found in metabolic variables such as glycaemia or the lipid profile. As expected, non-responders had a significantly lower CAR AUCi when compared to responders (p<0.001). However there was no difference in awakening cortisol concentration. Despite our hypothesis, no significant difference was found in general level of anxiety between the two groups. Finally, we analyzed aspects of human personality. We found that CAR responders scored significantly higher in character traits such as self-directedness (p=0.02), cooperativeness (p=0.03) and self-transcendence (p<0.01). Conclusion: The CAR differences in women with severe obesity are not associated with adiposity. Our data show that non-responders exhibit traits related to reduced self-determination and responsibility but also lower level of self-consciousness and helpfulness, which could be associated with a reduction in patient compliance and possibly less weight loss after surgery.