Subjective Cognitive Decline Is Associated with Health-Related Quality of Life in the Middle-Aged to Elderly Population

Background: Subjective cognitive decline (SCD) is considered to be a preliminary stage of dementia, and its prevalence is increasing with age. Objective: We aimed to study the association of SCD with health-related quality of life (HRQoL) in a large population-based sample. Methods: We analyzed data of the first 10,000 participants from the Hamburg City Health Study in Germany, a single center prospective cohort study, aged between 45 and 74 years that scored higher than 25 points in the Mini-Mental State Examination and had no known pre-existing dementia. HRQoL was assessed by the EQ-5D-5 L index, as well as the mental (MCS) and physical component summary (PCS) score of the Short Form-8. We computed linear regression analyses with 99% bias-corrected and accelerated (BCa) confidence intervals (CI) from 10,000 bootstrap samples to investigate the association between SCD and different indicators of HRQoL, while controlling for depression (PHQ-9), age, sex, and education as potential confounders. Results: Of 7,799 eligible participants (mean (SD) age 62.01 (8.41) years, 51.1% female), 3,708 (47.5%) reported SCD. Participants with SCD were older (62.7 versus 61.4 years) and more frequently female (54.2% versus 48.2%). SCD was independently associated with a lower EQ-5D-5 L index (beta=-0.01, 99% BCa CI = [-0.020, -0.003], p < 0.001) and PCS (beta=-1.00, 99% BCa CI = [-1.48, -0.51], p < 0.001) but not with MCS score. Conclusion: In a population of middle-aged to elderly participants, there is a significant negative association between SCD and HRQoL across different instruments of HRQoL measurement independent of depression, demographics, and education.