January 24, 2017 vol. 88 no. 4 371-378
Gilda E. Ennis, PhD, Yang An, MS, Susan M. Resnick, PhD, Luigi Ferrucci, MD, PhD, Richard J. O’Brien, MD, PhD and Scott D. Moffat, PhD
Objective: To examine whether long-term measures of cortisol predict Alzheimer disease (AD) risk.
Method: We used a prospective longitudinal design to examine whether cortisol dysregulation was related to AD risk. Participants were from the Baltimore Longitudinal Study of Aging (BLSA) and submitted multiple 24-hour urine samples over an average interval of 10.56 years. Urinary free cortisol (UFC) and creatinine (Cr) were measured, and a UFC/Cr ratio was calculated to standardize UFC. To measure cortisol regulation, we used within-person UFC/Cr level (i.e., within-person mean), change in UFC/Cr over time (i.e., within-person slope), and UFC/Cr variability (i.e., within-person coefficient of variation). Cox regression was used to assess whether UFC/Cr measures predicted AD risk…