Sensory Impairment and Subjective Cognitive Decline in Older Adults: A Cross-Sectional Study of Depression as Mediators in Southern China

Objective Subjective cognitive decline (SCD), the self-experienced onset of cognitive deterioration before deficits are measurable, is an early Alzheimer’s marker. Little is known about whether vision (VI), hearing (HI) or dual sensory impairment (DI) predicts SCD in Chinese older adults, or whether depressive symptoms mediate such links. Materials and Methods Cross-sectional community survey in Guangdong, January–October 2024. 1,162 participants aged 65–98 (mean 73.7 ± 6.8; 52.7% female). SCD was quantified with the 9-item Subjective Cognitive Decline Questionnaire; depression with PHQ-9; VI/HI by self-report. Multiple linear regression, subgroup and sensitivity analyses tested sensory–SCD associations; bias-corrected bootstrapping assessed mediation by depression. Results Overall SCD prevalence 42.9%. Relative to no impairment, severity of SCD was higher in HI (β = 0.589, 95% CI 0.229–0.949), VI (β = 1.597, 1.159–2.036) and DI (β = 2.072, 1.678–2.466) after full adjustment (p < 0.001). Effects were consistent across sex, residence, physical activity, nutrition, hypertension and diabetes; excluding smokers or individuals with hypertension/diabetes did not alter results. Depression mediated 6.8% of the VI–SCD effect and 4.7% of the DI–SCD effect (1,000 bootstrap samples), but mediation was non-significant for HI alone. Conclusion Sensory impairments, particularly concurrent VI and HI, are strongly associated with SCD in southern Chinese elders. Depressive symptoms partially explain these links, indicating a modifiable psychosocial pathway. Early detection and management of sensory loss and depression may help forestall subsequent