Increased nocturnal urinary cortisol levels in the elderly patients with depression, coexisting major geriatric syndromes and combined pathogenetic mechanisms

Background: The mechanisms at the basis of depression are still matter of debate, but several studies in the literature suggest common pathways with dementia (genetic predispositions, metabolic and inflammatory mechanisms, neuropathological changes) and other geriatric syndromes. Aims: To evaluate the role of cortisol (as marker of the HPA, hypothalamus-pituitary-adrenal axis hyperactivity) in elderly subjects with depressive symptoms (by the means of the AGICO, AGIng and COrtisol, study), in relationship to the presence of the major geriatric syndromes. Methods: The AGICO study enrolled patients from ten Geriatric Units in Italy. Every subject received a comprehensive geriatric assessment or CGA (including the Mini Mental State Examination or MMSE, Geriatric Depression Scale or GDS and Cornell Scale for Depression in Dementia or CSDD), the neurological examination (with a computed tomography scan or magnetic resonance imaging of the brain), the assessment of the metabolic syndrome (MetS), the evaluation of the cortisol activity by two consecutive urine collections (diurnal and nocturnal), a CGA-derived frailty index (FI) and a modified measure of allostatic load (AL). Results: The MMSE scores were significantly and inversely related to the values of GDS (p < 0.001) and CSDD (p < 0.05), respectively. The patients with depressive symptoms (GDS/CSDD > 8) showed significantly increased disability, MetS, inflammation, FI and AL and significantly reduced MMSE and renal function. The diurnal and nocturnal urinary cortisol levels in the patients with depressive symptoms (GDS/CSDD > 8) were higher with respects to controls (p < 0.05 for nocturnal difference). Discussion: The AGICO study showed that the stress response is activated in the patients with depression. Conclusion: The depression in elderly patient should be reconsidered as a systemic disease, with coexisting major geriatric syndromes (disability, dementia, frailty) and combined pathogenetic mechanisms (metabolic syndrome, impaired renal function, low-grade inflammation, and allostatic load). Cortisol confirmed its role as principal mediator of the aging process in both dementia and metabolic syndrome.