Genetic risk, adherence to a healthy lifestyle, and cognitive decline in African Americans and European Americans

Abstract

Introduction: We investigated the role of genetic risk and adherence to lifestyle factors on cognitive decline in African Americans and European Americans.

Methods: Using data from the Chicago Health and Aging Project (1993-2012; n = 3874), we defined the genetic risk based on presence of apolipoprotein E (APOE) $\epsilon 4$ allele and determined a healthy lifestyle using a scoring of five factors: non-smoking, exercising, being cognitively active, having a high-quality diet, and limiting alcohol use. We used linear mixed-effects models to estimate cognitive decline by genetic risk and lifestyle score.

Results: APOE $\epsilon 4$ allele was associated with faster cognitive decline in both races. However, within APOE $\epsilon 4$ carriers, adherence to a healthy lifestyle (eg., 4 to 5 healthy factors) was associated with a slower cognitive decline by 0.023 (95% confidence interval [CI] 0.004, 0.042) units/year in African Americans and 0.044 (95% CI 0.008, 0.080) units/year in European Americans.

Discussion: A healthy lifestyle was associated with a slower cognitive decline in African and European Americans.

Keywords: African Americans; European Americans; apolipoprotein E; cognitive decline; genetic epidemiology; lifestyle factors; race/ethnicity.

Figure 1.. Predicted 17-year rates of change in global cognition for a typical African American and typical European American according to their APOE ϵ4 status and adherence to a healthy lifestyle.

Abbreviations: APOE, apolipoprotein E; No. number; Dotted line shows the overall (not stratified by APOE ϵ4 status or lifestyle score) predicted rate of cognitive decline for a typical African American and European American. Models were adjusted for age, sex, education, comorbidities (heart disease, stroke, diabetes, or cancers) and their interaction with time.