Twenty-four-hour urinary free cortisol levels in vascular dementia and in Alzheimer's disease

During senescence, homeostatic and stress-response capacities are impaired, particularly in patients with dementia. Therefore, the study of the hypoth alamic-pituitary-adrenal (HPA) axis function, assuring the physiological ad aptation to the environmental stimuli, appears to be relevant. In this stud y we compared the 24-hour urinary free cortisol in patients with Alzheimer' s disease (AD), and with vascular dementia (VD). The AD patients were 15, m ean age 70 +/- 8 years (8 males and 7 females), the VD patients were also 1 5, mean age 71 +/- 9 years (11 males and 4 females), and we studied also 23 normal control subjects (C), mean age 68 +/- 9 years (15 males and 8 femal es). VD and AD were diagnosed according to the DSM-IV criteria. Subjects un der drug treatment, with depression or with illness which could influence H PA axis function, were not included. In all subjects, clinical history, psy chometric examination, computerized cerebral axial tomography were performe d. The statistical analysis was carried out with the Student's t-test. The 24-hour urinary cortisol levels were measured by using commercial RIA Kits (Radim, Pomezia, Italy). In AD the 24-hour urinary free cortisol was 53.18 +/- 17.49 mug/day, significantly higher than that of the C group (37.16 +/- 15.95 mug/day) (p < 0.001) and similar to that of the VD group (59.04 +/- 30.19 mug/day). Although a hyperactivity of HPA axis function is not a spec ific marker of dementia, our study in two forms of dementia with different etiology, like AD and VD, has revealed a common sign of hyperactivity of th e HPA axis function. We conclude that further studies of HPA axis may be he lpful for our understanding in the pathogenesis of dementia.