Given the reported differences in the incidence of clinical sub-types of cognitive impairment, the greater effect of the apoloipoprotein APOE E4 allele on dementia risk for females, and the fact that education, an established risk factor for dementia, is often lower for females, it has been recommended that the investigation of risk factors for cognitive decline should be conducted separately for males and females [28]. The gene discussed is APOE; the disease is dementia.