Hypothalamic-pituitary-adrenal (HPA) axis functioning in relation to body fat distribution.
OBJECTIVE
To relate hypothalamic-pituitary-adrenal (HPA) axis functioning and HPA feedback functioning to body fat distribution in normal weight to obese subjects.


METHODS
91 men and 103 women [age 18-45 years, BMI 19-35 kg/m(2), waist-to-hip ratio (WHR) 0.6-1.1].


METHODS
Anthropometry, body composition using hydrodensitometry and deuterium dilution method, cortisol variability by measuring 5-h cortisol concentrations, HPA axis feedback functioning using a dexamethasone suppression test, and HPA axis functioning under a challenged condition consisting of a standardized high-intensity test with ingestion of 4 mg dexamethasone.


RESULTS
In men, an inverse relationship was observed between 5-h cortisol exposure (nmol/ml) and fat mass index (FMI) (kg/m(2)) (r = -0.55, P < 0.001). In women, relationships were observed between 5-h cortisol exposure (nmol/ml.min) and WHR (r = -0.49, P < 0.001), maximal workload (r = 0.32, P < 0.001) as well as oral contraceptive use (r = 0.38, P < 0.001). Similarly, in men, an inverse relationship was observed between negative feedback expressed as baseline concentrations minus post dexamethasone cortisol concentrations (nmol/ml) and FMI (r = -0.53, P < 0.001). In women, relationships were observed between negative feedback expressed as baseline concentrations minus post dexamethasone cortisol concentrations (nmol/ml) and WHR (r = -0.43, P < 0.001), maximal workload (r = 0.30, P < 0.001) as well as oral contraceptive use (r = 0.43, P < 0.001) in women. Moreover, an inverse relationship was observed between HPA axis functioning in a challenged condition expressed as percentage increase of cortisol concentrations after standardized high-intensity test with ingestion of 4 mg dexamethasone (%) and waist circumference (r = -0.21, P < 0.10) in men and WHR (r = -0.21, P < 0.05) in women. In men, strong positive relationships were observed between FMI and waist circumference (r = 0.85, P < 0.001), as well as waist-to-hip ratio (r = 0.70, P < 0.001).


CONCLUSIONS
Disturbance of HPA axis functioning under basal and challenged conditions is related to visceral fat accumulation.
Rutters
Femke
F
Department of Human Biology, Maastricht University, Maastricht, The Netherlands. F.Rutters@hb.unimaas.nl
Nieuwenhuizen
Arie G
AG
Lemmens
Sofie G T
SG
Born
Jurriaan M
JM
Westerterp-Plantenga
Margriet S
MS
D000293:Adolescent; D000328:Adult; D001823:Body Composition; D050218:Body Fat Distribution; D015992:Body Mass Index; D003907:Dexamethasone / Q000008:administration & dosage; D005080:Exercise Test; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000032:analysis / Q000378:metabolism; D007030:Hypothalamo-Hypophyseal System / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D005082:Physical Exertion / Q000187:drug effects / Q000502:physiology; D010913:Pituitary-Adrenal System / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D012463:Saliva / Q000737:chemistry / Q000378:metabolism; D055105:Waist Circumference / Q000502:physiology; D055815:Young Adult
D003907:Dexamethasone; D006854:Hydrocortisone