Abstract
Background: Subjective cognitive decline (SCD) is a potential risk factor for dementia. We aimed to investigate the association between SCD and subsequent dementia in a nationwide population-based cohort in South Korea.Methods: This cohort included 579,710 66-year-old adults who completed a questionnaire about SCD and were followed-up for a total of 3,870,293 person-years (average 6.68 years per person). Hazard ratios were estimated using the Cox proportional hazards model and compared between subjects with and without SCD.Results: Compared to subjects without SCD, those with SCD were more likely to develop dementia (incidence per 100,000 person-years: no SCD: 566.14; SCD: 859.35). After adjusting for potential confounding factors, the risk of subsequent dementia significantly increased in subjects with SCD, with an adjusted hazard ratio (aHR) of 1.38 (95% confidence interval [CI] 1.34 to 1.41). The risk of subsequent dementia was greatly increased in subjects with higher SCD scores (aHR=2.77, 95% CI 2.47 to 3.11). A significant association between SCD and dementia was observed in both depressive and non-depressive symptom groups (aHR=1.50, 95% CI 1.42 to 1.57 in subjects with depressive symptoms; aHR=1.33, 95% CI 1.29 to 1.37 in subjects without depressive symptoms; P =0.001).Conclusions: In the participating 66-year-old population, SCD was significantly associated with an increased risk of subsequent dementia, independent of the presence of depressive symptoms. Our findings suggest that SCD indicates a risk for dementia. Further studies are needed to delineate potential approaches to preventing the development of dementia in individuals with SCD.
Precarious employment and new-onset severe depressive symptoms: a population-based prospective study in South Korea