APOE and Alzheimer disease: According to studies, ApoE4 is an independent risk factor for AD [10]. A Cohort study by Kivipelto et al., including 1449 AD patients, suggests that ApoE 4 is an independent risk factor for AD [43]. Another cohort study by Toro et al. also found the same association [44]. Other isoforms of ApoE are not as closely related to causing AD as ApoE4.