APOE and dementia: Beyond APOE, common disease‐associated variants identified from genome‐wide association studies (GWAS) (Harold et al., 2009; Hollingworth et al., 2011; Kunkle et al., 2019; Lambert et al., 2013; Naj et al., 2011) also modify dementia risk and can be used to calculate a polygenic risk score (PRS) (Tan et al., 2017; Chouraki et al., 2016; Cruchaga et al., 2018; Desikan et al., 2017; Escott‐Price et al., 2015; Sleegers et al., 2015; Lee et al., 2018).