Subjective cognitive decline and risk of MCI: the Mayo Clinic Study of Aging

Objective: We investigated different dimensions of subjective cognitive decline (SCD) to determine which was the best prognostic risk factor for incident mild cognitive impairment (MCI) among cognitively unimpaired (CU) participants.
Methods: We included 1167 CU participants, aged 70-95 years from the Mayo Clinic Study of Aging based on 2 concurrent SCD scales (part of the Blessed memory test and the 39-item ECog, which included a validated 12-item derivative) and a single question assessing worry about cognitive decline. We evaluated multiple ways to dichotomize scores. In continuous models we compared average scores on 4 ECog domains and multi-domain (39 and 12-item) ECog scores. Cox proportional hazard models were used to assess the association between each measure and risk of MCI in models adjusted for objective memory performance, depression, anxiety, sex, APOEε4 carriership and medical comorbidities.
Results: It was possible to select a substantial group of participants (14%) at...