STRESS-RELATED CORTISOL SECRETION IN MEN - RELATIONSHIPS WITH ABDOMINAL OBESITY AND ENDOCRINE, METABOLIC AND HEMODYNAMIC ABNORMALITIES

Abdominal obesity has been suggested to be associated with perturbatio ns of the regulation of the hypothalamic-pituitary-adrenal (HPA) axis. In a population of 51-yr-old men (n = 284) salivary cortisol concentr ations were determined on repeated (n = 7) occasions over a random wor king day, and perceived stress was reported in parallel. Cortisol valu es were then related to reported stress (stress-related cortisol). A s tandardized lunch was used as a physiological challenge. A low dose (0 .5 mg) dexamethasone suppression test was also performed as well as de terminations of testosterone and insulin-like growth factor I (IGF-I). Body mass index [weight (kilograms)/height (meters)(2)]; waist/hip ci rcumference ratio (WHR); sagittal trunk recumbent diameter (D); fastin g insulin; blood glucose; triglycerides; and total, low density (LDL), and high density (HDL) lipoprotein cholesterol were also determined. Cortisol concentrations were highest in the morning, and lunch was fol lowed by a peak. (P = 0.044). Two types of diurnal cortisol curves wer e identified, one characterized by a high variability with high mornin g values, and another with low variability and low morning values. Bot h correlated strongly with suppression of salivary cortisol by dexamet hasone (P < 0.001). Stress-related cortisol secretion was associated w ith D (P = 0.051), low IGF-I (P = 0.006), and diastolic blood pressure (P = 0.078). When the type of diurnal cortisol curve was taken into c onsideration by statistical weighting, stress-related cortisol secreti on in subjects with high variability showed associations with testoste rone (P < 0.001), D, total and LDL cholesterol, diastolic blood pressu re (P < 0.001), fasting insulin (P = 0.039), and glucose (P = 0.030) a s well as, negatively, triglycerides (P < 0.001). When weighted for a low variability of diurnal cortisol secretion, stress-related cortisol secretion showed strong negative relationships with IGF-I, testostero ne, and HDL. Furthermore, strong, consistent relationships tall P < 0. 001) were found with obesity factors (body mass index, WHR, and D), an d with metabolic (insulin, glucose, triglycerides, and total and LDL c holesterol) as well as hemodynamic variables (systolic and diastolic b lood pressure and heart rate). These results clearly show interactions between diurnal cortisol secretion related to perceived stress and an thropometric, endocrine, metabolic, and hemodynamic variables. This se ems to occur with apparently normal regulation of the HPA axis (high m orning peaks and variability as well as dexamethasone suppression of c ortisol), where other endocrine variables are not affected. With a low diurnal cortisol variation and blunted dexamethasone suppression, ind icating abnormal regulation of the HPA axis, perceived stress-dependen t cortisol values were strongly related to perturbations of other endo crine axes as well as abdominal obesity with metabolic and hemodynamic abnormalities. Perturbations of the regulation of the KPA axis such a s those described in combination with low dexamethasone suppressibilit y are known to follow long term overactivation of the axis by factors such as environmental stress.