Obesity and the hypothalamic-pituitary-adrenal axis in adolescent girls

• Type of Material: Article
• Authors: JB Hillman, Cincinnati Children's Hospital Medical Center; LD Dorn, Cincinnati Children's Hospital Medical Center; Tammy Loucks, Emory University; SL Berga, Emory University
• Language: English
• Date: 2012-03-01
• Publisher: Elsevier: 12 months
• Publication Version: Author Accepted Manuscript (After Peer Review)
• Copyright Statement: © 2012 Elsevier Inc. All rights reserved.
• Final Published Version (URL): http://dx.doi.org/10.1016/j.metabol.2011.07.009
• Title of Journal or Parent Work: Metabolism
• ISSN: 0026-0495
• Volume: 61
• Issue: 3
• Start Page: 341
• End Page: 348
• Grant/Funding Information: This research was supported by grant R01 DA 016402 from the National Institute of Drug Abuse (PI: Dr. Dorn); in part by USPHS grant UL1RR026314 from the National Center for Research Resources, NIH; and by grant 1K12 HD051953 from the National Institute of Health/Office of Research on Women’s Health (Dr. Hillman).
• Keywords: CHILDREN; GLUCOSE-TOLERANCE; ABDOMINAL OBESITY; DEPRESSIVE SYMPTOMS; ADIPOSITY; WOMEN; Science & Technology; Endocrinology & Metabolism; ASSOCIATION; BODY-FAT DISTRIBUTION; STRESS; CORTISOL SECRETION; Life Sciences & Biomedicine
• Research Categories: Health Sciences, Obstetrics and Gynecology; Health Sciences, Medicine and Surgery

Abstract

Stress and stress-related concomitants, including hypothalamic-pituitary- adrenal (HPA) axis activation, are implicated in obesity and its attendant comorbidities. Little is known about this relationship in adolescents. To begin to address this important knowledge gap, we studied HPA axis activity in 262 healthy adolescent girls aged 11, 13, 15, and 17 years. We hypothesized that obesity would be correlated with increased HPA axis activity and reactivity. Measures of HPA axis activity included 3 blood samples obtained midday (between 1:00 and 2:00 pm) over the course of 40 minutes; overnight urine free cortisol; and cortisol levels 0, 20, and 40 minutes after venipuncture (cortisol reactivity). Measures of adiposity included body mass index (BMI), BMI z score (BMI-Z), percentage body fat, and fat distribution (central adiposity) assessed by dual-energy x-ray absorptiometry. Daytime levels of serum cortisol were inversely associated with BMI-Z and central adiposity (P <.05). The urine free cortisol excretion rate was positively correlated with BMI, BMI-Z, and central adiposity. There was blunting of cortisol response to venipuncture with increasing adiposity. Our results suggest that there may be reduced cortisol levels during the day and increased levels at night with increasing degree of adiposity. This study provides preliminary findings indicating an alteration of the circadian rhythm of cortisol with obesity. We conclude that obesity is associated with altered HPA activity in adolescent girls. The clinical implications of our findings require further investigation.