Cortisol secretion and Alzheimer's disease progression: a preliminary report

We report preliminary findings in a study of the relationship of plasma cortisol concentration (CORT) to the clinical progression of Alzheimer's disease (AD), testing the hypotheses that CORT predicts AD progression and that CORT increases as the disease advances. In 12 subjects with NINCDS/ADRDA probable AD, we performed cognitive testing and plasma cortisol determinations at baseline and again in 12 months. A modified Alzheimer's Disease Assessment Scale-Cognitive (ADAS-COG) measured disease progression. Plasma cortisol concentration CORT was determined at 12 AM and 1 PM, and an Afternoon Cortisol Test (ACT) was used to estimate average 24-hr CORT. Baseline 12 AM CORT correlated with the change in ADAS-COG from start of study to 12 months. No cortisol measure increased over the study period; estimated average 24-hr CORT and 12 AM CORT remained constant, whereas while 1 PM CORT declined. There was no relationship between age or duration of illness and any of the cortisol measures at baseline.