Participants will be given a full information of the study and written informed consent should be obtained before entering the study. Participants will take part in 5 visits over the course of 12 months. If participants have taken cholesterol lowering drug, they will have wash-out period at least 4weeks. Participants will undergo 8 tests (ADAS-Jcog etc., baseline and month 12 visits), complete a medical history questionnaire (baseline), complete medication side effect review through questionnaire and/or blood sample (all visits). Participants will be randomly assigned to receive either pitavastatin or other cholesterol lowering medication for 12 months.