Data from: 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 increased
risk of incident MCI based on combined baseline endorsement of any
consistent SCD on the ECog (any item scored ≥3; HR 12-item ECog 2.17
[1.51-3.13]) and worry (HR 1.79 [1.24-2.58]) in an adjusted model
combining these dimensions. In continuous models, all ECog domains and the
multi-domain scores were associated with risk of MCI with a small
advantage for multi-domain SCD (HR 12-item ECog 2.13 [1.36-3.35] per point
increase in average score). Information provided by the informant
performed comparable to self-perceived SCD. Conclusion: Prognostic value
of SCD for incident MCI improves when both consistency of SCD and
associated worry are evaluated.