Sex/gender differences in cognitive impairment have been approached considering both biological and social factors: While biological factors (e.g. effects of apolipoprotein E ε 4 genotype and gonadal hormones) can cause sex differences in health, particularly cognitive impairment, behavioural risk factors and social determinants also seem important in explaining gender differences [13–18, 21–25]. Here, APOE is linked to Cognitive impairment.