Relationship Between the Severity of Subjective Cognitive Decline and Health-Related Quality of Life in Community-Dwelling Older Adults: A Cross-Sectional Study Focusing on Sex Differences

Background/Objectives: Sex differences in the relationship between subjective cognitive decline (SCD) and health-related quality of life (HRQOL), as well as psychological and physical factors affecting this relationship, have not been fully investigated. In this study, we aimed to examine the relationship between SCD severity and HRQOL in community-dwelling older adults in Japan and to clarify the psychological and physical factors affecting this relationship by sex. Methods: This cross-sectional study included 456 community-dwelling older adults and was conducted in September 2024. SCD severity was evaluated using the visual analog scale, and HRQOL was assessed using the EuroQol 5-Dimensions 5-Levels. Psychological factors (depression and insomnia) and physical factors (pain and frailty) were measured, and the relationship between SCD and HRQOL was analyzed by sex. Results: In women, HRQOL decreased as SCD severity increased and was associated with depression, insomnia, and physical pain. Conversely, in men, the association between SCD and HRQOL was not significant, and HRQOL was mainly associated with physical health factors, including pain and frailty. Conclusions: There were sex differences in the relationship between SCD and HRQOL, with women’s awareness of SCD associated with a decline in HRQOL, whereas physical health was the main determinant in men. Sex-specific interventions with psychological support being effective for women and support focusing on maintaining physical health for men are warranted.