APOE and diabetes mellitus: Kuo et al., for instance, compared the APOE gene polymorphism with COVID-19 infection by logistic regression in a cohort of 622 participants in the United Kingdom and showed that patients with the ε4/ε4 genotype were more likely to be infected by COVID-19 (OR = 2.31, 95% CI: 1.65–3.24, p = 1.19 × 10−6) regardless of history of diabetes, cardiovascular disease, or dementia [6].