APOE and diabetes mellitus: In contrast, Byun et al39 recently reported that Aβ-positive patients with preclinical AD showed reduced inner nasal macular thickness and RNFL thickness compared with Aβ-negative patients.39 Second, numerous parameters besides the selected confounding variables of age, sex, education level, diabetes, hypertension, and APOE ε4 status could also influence cognitive function; thus, strict adjustments might not be feasible.