Heterogeneity in Measures and Rates of Reported Dementia and Subjective Memory Complaints Across U.S. National Surveys

Abstract

Objectives: Several U.S. health surveillance surveys contain items related to self- and proxy reports of dementia and subjective memory complaints (SMC). Despite their similar content, these items differ in terminology, item specificity, and time frame. The goal of this study was to analyze whether item features might influence endorsement rates for dementia and SMC. Methods: We calculated design-appropriate estimates for the endorsement of dementia and SMC across U.S.-based national surveys and employed pairwise comparisons to evaluate endorsement rates across surveys. We also examined item characteristics to explore possible effects on endorsement rates. Results: Endorsement rates were wide-ranging for dementia (ranging from 2.7% to 9.9%) and SMC (5.6% to 46.6%). Pairwise comparisons revealed statistically significant differences on most dementia-related items (76%), and all SMC comparisons (100%). Items varied substantially in the terminology used to assess dementia and SMC (e.g., “dementia” vs “Alzheimer’s disease”) and used different time frames (e.g., “past month” vs “5 years”). Discussion: National survey data on reported dementia and SMC can have important research, training, and policy implications, yet endorsement rates vary widely across surveys. That variability could emerge from subtle but influential item characteristics, and our findings highlight the need for item harmonization, in even their most basic characteristics. Standardizing items across national surveillance surveys facilitates comparison across surveys so that we can better understand the true burden of these conditions to inform public health initiatives.