Cortisol and dehydroepiandosterone sulfate plasma levels and their relationship to aging, cognitive function, and dementia.

We have studied the relationship between dehydroepiandrosterone sulfate (DHEAS), cortisol, and cognitive function in a population of demented patients (n=29), age-matched controls (n=46), and younger subjects (n=11). All were submitted to morning collection of blood for determination of plasma cortisol and DHEAS measured by 125I radioimmunoassay. DHEAS levels and cortisol/DHEAS ratios were significantly different among groups with higher DHEAS levels and lower cortisol/DHEAS ratios in younger people (Bonferroni p<.05). Cortisol levels were associated to the presence of dementia (Odds ratio=.93; 95% CI,.86-1.01). There was no difference between DHEAS levels of demented and age-matched controls; however, demented patients showed a trend for higher cortisol/DHEAS ratios than age-matched controls and the latter showed higher ratio values than younger subjects. DHEAS and cortisol plasma values were significantly correlated in all individuals (p<.01). In this study cortisol was independently associated to the presence of dementia.