Choline helps reduce Alzheimer's risk for certain people: a new study

The following is a bullet-point summary of a recently published research. Specifically, this is a layman's summary of a medical news article, "APOE4 Alzheimer’s Risk Could Be Abated by Common Dietary Supplement", published on ClinicalOMICS magazine, supplemented with other information such as that on Wikipedia.

• The primary authors of the published research article work for MIT.
• People carry APOE (Apolipoprotein E) genes, which are involved in the metabolism of fats. The APOE2 variant is good, 3 neutral, 4 bad in terms of risks for late onset Alzheimer, as well as cardiovascular diseases. 14% of the general population, but almost half of Alzheimer's patients, have APOE4. Most people have APOE3.
• The Wikipedia page for choline states that "[s]tudies observing the effect between higher choline intake and cognition have been conducted in human adults, with contradictory results". And WebMD article says "Insufficient Evidence for ... Alzheimer disease". But the authors of this new study said "those trials were not targeted specifically to people with the APOE4 gene".
• "[C]holine supplementation ameliorated the APOE4-induced lipid defects... [M]ost people don’t consume that much [of recommended choline]... [P]eople who carry the APOE4 gene may benefit from taking choline supplements... The APOE4 carriers are more susceptible to choline deficiency."
• According to Wikipedia, beef liver contains the most choline per unit weight, 418.22 mg/100g, followed by chicken liver (290.03 mg/100g), hen egg (251.00), "wheat germ, toasted" (152.8), bacon (124.89), soy bean (115.87), pork loin (102.76). Vegetables are not rich sources of choline; the highest are brussels sprout (40.61) and broccoli (40.06), followed by cauliflower (39.10).
• Choline is not considered vitamin. Multivitamins you may be taking do not contain choline. Severe deficiency, which is unlikely, "causes muscle damage and non-alcoholic fatty liver disease" according to Wikipedia.