SAT-367 Variations in Serum Morning Cortisol Levels Based on Sex and Pubertal Status

Abstract

Introduction: Cortisol plays a vital role in health, with adrenocortical insufficiency often resulting in serious adverse events. Patients with suspected adrenal insufficiency often undergo initial screening with an 8 am serum cortisol level. Values below 13 μg/dL are suggestive of adrenal insufficiency1 and confirmatory testing with an ACTH stimulation test is performed. However, much of the data collected to determine appropriate cut-off values for morning cortisol levels has been focused in the adult population, and does not account for effects that sex and pubertal status may have upon cortisol levels in the pediatric population. The purpose of this study was to evaluate the mean morning cortisol level in the pediatric population based on Tanner staging and sex in order to better understand their influences on laboratory evaluation of adrenal insufficiency. Methods: A retrospective chart review was conducted using electronic medical records of 107 patients seen at Children’s Mercy Kansas City from 11/01/2007 to 11/01/2017. Patients between 2-17 years of age who had pubertal staging assessed by a pediatric endocrinologist and confirmed adrenal sufficiency by high-dose ACTH stimulation testing were included. Two-tailed t-tests were used to compare mean morning cortisol levels between females and males by Tanner stage, and mean morning cortisol levels between females and males. Results: In this cohort, 58 patients were classified as Tanner 1 (pre-pubertal) and 49 patients were classified as Tanner 2-5 (pubertal to post-pubertal). Sex was evenly distributed with 53 females and 54 males. Mean morning cortisol levels differed between Tanner 1 females and males at 11.69±5.24 μg/dL and 7.47±3.77 μg/dL, respectively (p= 0.0007); however, there were no differences in mean morning cortisol levels between Tanner 2-5 males and females (p=0.6096). Overall, mean morning cortisol levels differed in females and males independent of Tanner staging at 11.46 ± 5.99 μg/dL and 8.65 ± 3.83 μg/dL, respectively (p= 0.0049). No difference was found in mean morning cortisol levels between Tanner 1 and Tanner 2-5 subjects independent of sex (p= 0.0932). Discussion: This data suggests that a serum morning cortisol value <13 μg/dL may not be an appropriate cut-off value for adrenal insufficiency screening in the pediatric population, and that a lower value may be more reflective of normal cortisol secretion. Additionally, different normative values may need to be established for pediatric females and males. Larger, prospective studies are needed to evaluate the role of sex and pubertal status in identifying adrenal insufficiency in the pediatric population.