APOE and hippocampal atrophy: In accordance with the findings of one previous study [56] that being underweight could increase the risk of dementia, we further demonstrated lower BMI predicted faster rates of hippocampal atrophy and cognitive decline in APOE-ε4 non-carriers, implying underweight may be also a risk factor of AD in non-demented elder adults without APOE-ε4 allele.