Thicker macula in asymptomatic APOE epsilon 4 fiddle-aged adults at high AD risk

Introduction: We compared retinal layers' thickness between apolipoprotein E (APOE) epsilon 4 carriers and non-carriers in a cohort of cognitively normal middle-aged adults enriched for Alzheimer's disease (AD) risk. Methods: Participants (N = 245) underwent spectral domain optical coherence tomography. Multivariate analyses of covariance adjusting for age, sex, education, and best corrected vision acuity was used to compare retinal thickness between APOE groups. Results: Participants' mean age was 59.60 (standard deviation = 6.42) with 66.4% women and 32.2% APOE epsilon 4 carriers. Greater macular full thickness was observed in APOE epsilon 4 carriers compared to non-carriers (P = .017), reaching statistical significance for the inner and outer nasal (P = .009 and P = .005, respectively), inner superior (P = .041), and inner and outer inferior (P = .013 and P = .033, respectively) sectors. The differences between APOE groups were mainly driven by the ganglion cell layer (P < .05) and the inner plexiform layer (P <.05). Discussion: A thicker macula is observed already in midlife asymptomatic APOE epsilon 4 carriers at high AD risk.