Apolipoprotein E4 Genotype and Depressive Symptoms as Risk Factors for Dementia in an Older Korean Population

OBJECTIVE Growing evidence suggests the separate associations of apolipoprotein E e4 allele (apo E4) and depression with incident dementia. This study investigated the separate and combined effects of apo E4 and depression on the incidence of dementia in both men and women. METHODS Of 625 elderly without dementia at baseline, 518 (83%) were followed over a 2.4-year period and were assessed clinically for incident dementia. The apo E polymorphism was ascertained, and depression was identified using the Korean version of the Geriatric Depression Scale (KGDS). Covariates included age, gender, education, disability, alcohol history, physical activity, and vascular risk factors. RESULTS The incidence of dementia was significantly higher in elderly Koreans with both apo E4 and depression compared to those without both factors [adjusted odds ratio (95% CI)=5.85 (1.77-19.38)]. This interaction was significant in men (p=0.049), but not in women (p=0.354). CONCLUSION Depressed elderly people are at great risk for incident dementia in the presence of apo E4. Potential gender differences require further evaluation.