A multilevel analysis of the influence of Apolipoprotein E genotypes on depressive symptoms in late-life moderated by the environment

Abstract

Objective This study aimed to clarify the relationship between the APOE alleles and depressive symptoms of older adults, considering individual characteristics and the effect of neighborhood environment. Methods Using a multilevel, stratified sampling strategy, 500 elders were recruited from official household records. Depressive symptoms were assessed using the Taiwanese Depression Questionnaire [TDQ]. Cognitive function was assessed by the Short Portable Mental Status Questionnaire [SPMSQ]. Blood samples were collected for the determination of the Apolipoprotein E [APOE] polymorphism. Perceived neighborhood experience was brought together using the Neighborhood Quality Index [NQI]. Results Three hundred and three subjects (58.8% male, with a mean age of 69.2 [SD = 2.7] years) completed all questionnaires and the collection of blood samples. Risk factors for depressive symptoms of elders included lower educational level, cognitive impairment, having 2 or more chronic diseases, and having the APOE ɛ4 allele. In the 2-level model with individual characteristics and neighborhood environmental factors, the effect of the APOE ɛ4 allele on depressive symptoms was significantly attenuated. Conclusions The APOE ɛ4 allele is correlated with depressive symptoms among older adults, but moderated by neighborhood environmental factors.