Sleep quality and subjective cognitive decline in middle-aged and older adults

The purpose of this study was to examine whether subjective cognitive decline (SCD) is associated with sleep quality among adults aged ≥ 45 and to identify subgroups needing targeted sleep-management approaches. Cross-sectional analysis of the 2018 Korea Community Health Survey (N = 136,237; ≥45 years). Sleep quality was assessed with the PSQI-K and analyzed as a binary outcome (PSQI > 5 = poor sleep) and continuous outcome (total score 0–21). SCD was defined by self-reports of increasingly frequent or severe confusion/poor memory in the past year. Covariates were selected using Andersen’s behavioral model. We used survey-weighted logistic and linear regression to estimate adjusted odds ratios (AORs) and β coefficients and conducted subgroup analyses by age group (45–64 vs. ≥65) and history of depression. Overall, 38.6% had poor sleep and 23.5% reported SCD. Poor sleep prevalence was 54.6% in those with SCD versus 33.7% without. Adjusted models showed SCD was associated with higher odds of poor sleep (AOR 1.84, p < 0.001) and higher PSQI score (β = 1.09, p < 0.001). Associations were stronger in middle-aged adults (45–64) and individuals with a history of depression. SCD is linked to poorer sleep quality among adults ≥45, particularly in middle-aged and depressed subgroups. These findings support prioritized screening and integrated interventions addressing cognitive complaints, sleep, and mood—especially in working-age populations.