OBJECTIVE: To assess the relationships between the regulation of diurnal and food-induced cortisol secretion and anthropometric, metabolic and haemodynamic variables in middle-aged men. SUBJECTS AND METHOD: Salivary cortisols were collected repeatedly (n =7) over an ordinary working day (8 a.m. to 11 p.m.) in a randomly selected population of 284 men, aged 51 y. A standardized lunch was provided, and an overnight low-dose dexamethasone suppression test was performed. These measurements were correlate with the anthropometric factors¾body mass index, BMI, (kg/m2), waist-to-hip ratio (WHR) and abdominal sagittal diameter; the metabolic factors¾fasting insulin and glucose as well as their ratio, and triglycerides; and the haemodynamic factors¾systolic and diastolic blood pressures and heart rate. RESULTS: As reported previously two principal types of salivary cortisol secretory patterns can be singled out, one characterized by high morning cortisol levels, a normal circadian rhythm and feedback regulation (dexamethasone) along with a brisk cortisol response to lunch, and another, found in a limited number of men, characterized by low morning cortisols, the absence of a circadian rhythm, a relative resistance to dexamethasone inhibition and a poor lunch-induced cortisol response. The normal cortisol secretory pattern showed negative associations with BMI (P<0.05), WHR (P<0.01), and blood pressures (P<0.001). After stimulation by food intake, negative relationships were found with all obesity measurements, insulin, insulin/glucose ratio, triglycerides, blood pressures and heart rate (all P<0.001). These results suggest that normally regulated cortisol is associated with a favourable somatic health. In contrast, after food intake cortisol secretion, based on an abnormal cortisol secretory pattern, showed consistent positive associations with obesity measurements, insulin, glucose and insulin/glucose ratio, triglycerides, blood pressures and heart rate (all P<0.001). CONCLUSIONS: A normal HPA axis regulation is associated with excellent health anthropometric, metabolic and haemodynamic variables, particularly visible after the physiological stimulus of food intake. This is, however, not the case in men with perturbed HPA axis function where associations in these somatic variables become exaggerated by food intake. We have previously reported that perceived stress-related cortisol is associated with abnormalities in the variables mentioned above, both with a normal and, particularly, with an abnormal function of the HPA axis. It is thus apparent that perceived stress and food intake show separate associations to somatic variables with a normally functioning HPA axis, while with an abnormal regulation of this axis both perceived stress and food intake exaggerate associations to abnormal somatic variables. International Journal of Obesity (2000)24, 416-422 |
