The relationship between subjective cognitive decline and demographic characteristics is moderated by study setting: Findings from the SCD‐I Item Analysis Working Group

Abstract

AbstractBackgroundSubjective Cognitive Decline (SCD) in the absence of objective cognitive impairment has been linked to progression to Alzheimer’s Disease and Related Disorders dementia. Demographic characteristics might bias the measurement of SCD, but it remains unclear how these characteristics relate to SCD. As part of the international SCD‐I item analysis working group, we previously harmonized item‐level SCD questionnaires from cognitive aging studies in North America and Europe into a subjective cognition factor (SCF) score. Here, we aimed to investigate the relationship between SCF and demographic characteristics, as well as the potential moderating role of community‐based versus memory specialty clinic settings.MethodIn this cross‐sectional study, data from 13 international aging studies was included (N=4,979 cognitively normal participants, mean age 75±8, 61% female). Over 600 different SCD questionnaire items were harmonized into the SCF score using item response theory modeling. A series of univariate multilevel linear regression analyses were performed to investigate the relationship between age, gender, education and SCF, with setting (community‐based versus memory clinic) included as fixed factor.ResultAfter multilevel adjustment for study clustering, lower SCF, indicating worse subjective cognitive functioning, was associated with older age, such that a 10 year difference in age was associated with a 0.05 standard deviation lower SCF (p=.04, see Table 1). Females reported better subjective cognitive functioning (B=.07, p<.01). No association with education was found across settings. When stratified, the relationships between SCF, gender and age were apparent in the community‐based but not the memory clinic‐based settings (see Table 1).ConclusionThis is the first study using the harmonized SCF score to study the relationship between SCD and demographic characteristics. This SCD metric applicable across studies could serve as a major facilitator in studying SCD. We found men and older individuals to report slightly lower levels of subjective cognitive functioning, driven by the community‐based setting. These findings suggest that relationships between age and SCD may be different among people motivated to seek medical attention for their cognition compared to unselected individuals in the community.