The APOE-E4 allele and the risk of functional decline in a community sample of African American and white older adults

Background. Given previous findings of adverse health outcomes associated w ith the E4 allele, data from a biracial community sample of older adults we re used to determine whether functional decline is associated with the apol ipoprotein E (APOE) E4 allele. Methods. In 1986, a stratified random household sample of community residen ts 65 years of age and older (it 4162) formed the Duke Established Populati ons for Epidemiologic Studies of the Elderly. Of those available 6 years la ter, 78.4% (n = 1999) were genotyped, providing "baseline" data at this tim e. The available survivors (n = 1529) provided longitudinal data 4 years la ter. Using longitudinal data from this sample, a combination of measures as sessing self-care capability, instrumental activities of daily living (IADL ), and mobility was obtained at baseline and 4 years later (n = 1529) to de termine the extent to which the E4 allele affected change in functional sta tus. Functional status was assessed using items front a modified Katz Activ ities of Daily Living (ADL) Scale. the Older American Resources and Service s IADL scale, and the Rosow-Breslau physical health scale. Control measures included demographic characteristics, depression. health status, arthritis , and cognitive status. APOE was coded as E4 present versus absent. Results. APOE E4 was not associated with decline in functional status in ei ther bivariate or multivariate analyses as a main effect. There were, howev er, statistically significant interactions of the E4 allele with gender and baseline functional status, with greater functional decline in women with the E4 allele, whereas those with poorer baseline functioning who had the E 4 allele were less likely to decline. No significant racial differences wer e found. Conclusions. Despite the documented association of the E4 allele of APOE wi th adverse health outcomes, the E4 allele was not associated with a decline in functional status as a main effect. Interactions of E4 with gender (bei ng female) and baseline functional status, however, did predict functional decline.