Absence of Circadian Salivary Cortisol Rhythm in Women with Anorexia Nervosa

Study Objective To compare the cortisol levels and 24 hour salivary cortisol rhythm in patients with anorexia nervosa (AN) and normal controls. Design Prospective transversal controlled study. Setting Tertiary-referral University Hospital. Participants Twenty-five patients aged 15 to 35 years, 13 of them with regular ovulatory cycles, and 12 with diagnosis of AN. Interventions Salivary and blood collection for cortisol 24-hour rhythm determination. Main Outcome Salivary cortisol was determined at 9 am, 5 pm, and 11 pm. Seric follicle-stimulating hormone, luteinizing hormone (LH), prolactin, estradiol (E2), progesterone, dehydroepiandrosterone-S (DHEA-S), and cortisol were sampled together with the 9 am salivary sample. Results LH, E2, and DHEA-S levels were reduced in patients with AN. A correlation between salivary and serum cortisol levels was observed in the 9 am sample only in controls (r = 0.67, P = 0.01; AN: r = 0.48, P = 0.12). Cortisol rhythm was present in all control subjects, whereas it was absent in one third of AN patients. The area under the curve for the AN group with preserved rhythm was significantly higher than for the control group (Me = 6811 ng/dl/24h vs 3708 ng/dl/24 h; P = 0.034). Conclusion Patients with AN have higher salivary cortisol levels when compared to normal women and some of them do not present circadian rhythm.