* evidence of dementia and/or significant cognitive impairment on screening (i.e: blind montreal cognitive assessment \[moca\] score \<19/22 in conjunction with clinical assessment) * severe co-morbid medical or psychiatric condition that prevents participation * history of traumatic brain injury with loss of consciousness (\>30 mins) within the last 2 years * ongoing long-term use for a clear indication (e.g. secondary cardiovascular prevention in high-risk individuals) or any contraindication (e.g. previous adverse reaction) of statin use * evidence of severe or significant liver disease, defined as any of the following: acute viral hepatitis; chronic active hepatitis; chronic active hepatitis; cirrhosis; or elevated biochemical function markers i.e. alt or ast \>3x the uln or egfr \<30ml/min/1.73m2 * creatine kinase (ck) levels \> 2x upper limit of normal (uln) * female of child-bearing potential that is unable or unwilling to use reliable method of contraception, breastfeeding, or planning a pregnancy * for a sub-group of participants undergoing mri - any contraindication to mri due to metallic body parts or claustrophobia * medical history of a disorder that might, in the opinion of the attending clinician, put the participant at significant risk if they were to participate in the trial

* evidence of dementia and/or significant cognitive impairment on screening (i.e: blind montreal cognitive assessment \[moca\] score \<19/22 in conjunction with clinical assessment) * severe co-morbid medical or psychiatric condition that prevents participation * history of traumatic brain injury with loss of consciousness (\>30 mins) within the last 2 years * ongoing long-term use for a clear indication (e.g. secondary cardiovascular prevention in high-risk individuals) or any contraindication (e.g. previous adverse reaction) of statin use * evidence of severe or significant liver disease, defined as any of the following: acute viral hepatitis; chronic active hepatitis; chronic active hepatitis; cirrhosis; or elevated biochemical function markers i.e. alt or ast \>3x the uln or egfr \<30ml/min/1.73m2 * creatine kinase (ck) levels \> 2x upper limit of normal (uln) * female of child-bearing potential that is unable or unwilling to use reliable method of contraception, breastfeeding, or planning a pregnancy * for a sub-group of participants undergoing mri - any contraindication to mri due to metallic body parts or claustrophobia * medical history of a disorder that might, in the opinion of the attending clinician, put the participant at significant risk if they were to participate in the trial

evidence of dementia and/or significant cognitive impairment on screening (i.e: blind montreal cognitive assessment [moca] score <19/22 in conjunction with clinical assessment) severe co-morbid medical or psychiatric condition that prevents participation history of traumatic brain injury with loss of consciousness (>30 mins) within the last 2 years ongoing long-term use for a clear indication (e.g. secondary cardiovascular prevention in high-risk individuals) or any contraindication (e.g. previous adverse reaction) of statin use evidence of severe or significant liver disease, defined as any of the following: acute viral hepatitis; chronic active hepatitis; chronic active hepatitis; cirrhosis; or elevated biochemical function markers i.e. alt or ast >3x the uln or egfr <30ml/min/1.73m2 creatine kinase (ck) levels > 2x upper limit of normal (uln) female of child-bearing potential that is unable or unwilling to use reliable method of contraception, breastfeeding, or planning a pregnancy for a sub-group of participants undergoing mri - any contraindication to mri due to metallic body parts or claustrophobia medical history of a disorder that might, in the opinion of the attending clinician, put the participant at significant risk if they were to participate in the trial

evidence of dementia and/or significant cognitive impairment on screening (i.e: blind montreal cognitive assessment [moca] score <19/22 in conjunction with clinical assessment) severe co-morbid medical or psychiatric condition that prevents participation history of traumatic brain injury with loss of consciousness (>30 mins) within the last 2 years ongoing long-term use for a clear indication (e.g. secondary cardiovascular prevention in high-risk individuals) or any contraindication (e.g. previous adverse reaction) of statin use evidence of severe or significant liver disease, defined as any of the following: acute viral hepatitis; chronic active hepatitis; chronic active hepatitis; cirrhosis; or elevated biochemical function markers i.e. alt or ast >3x the uln or egfr <30ml/min/1.73m2 creatine kinase (ck) levels > 2x upper limit of normal (uln) female of child-bearing potential that is unable or unwilling to use reliable method of contraception, breastfeeding, or planning a pregnancy for a sub-group of participants undergoing mri - any contraindication to mri due to metallic body parts or claustrophobia medical history of a disorder that might, in the opinion of the attending clinician, put the participant at significant risk if they were to participate in the trial

- evidence of dementia and/or significant cognitive impairment on screening (i.e. blind montreal cognitive assessment [moca] score <19/22) - severe co-morbid medical or psychiatric condition that prevents participation - history of traumatic brain injury with loss of consciousness (>30 mins) within the last 2 years - ongoing long-term use for a clear indication (e.g. secondary cardiovascular prevention in high-risk individuals) or any contraindication (e.g. previous adverse reaction) of statin use - evidence of severe or significant liver disease, defined as any of the following: acute viral hepatitis; chronic active hepatitis; chronic active hepatitis; cirrhosis; or elevated biochemical function markers i.e. alt or ast >3x the uln or egfr <30ml/min/1.73m2 - creatine kinase (ck) levels > 2x upper limit of normal (uln) - female of child-bearing potential that is unable or unwilling to use reliable method of contraception, breastfeeding, or planning a pregnancy - for a sub-group of participants undergoing mri - any contraindication to mri due to metallic body parts or claustrophobia - medical history of a disorder that might, in the opinion of the attending clinician, put the participant at significant risk if they were to participate in the trial

- evidence of dementia and/or significant cognitive impairment on screening (i.e. blind montreal cognitive assessment [moca] score <19/22) - severe co-morbid medical or psychiatric condition that prevents participation - history of traumatic brain injury with loss of consciousness (>30 mins) within the last 2 years - ongoing long-term use for a clear indication (e.g. secondary cardiovascular prevention in high-risk individuals) or any contraindication (e.g. previous adverse reaction) of statin use - evidence of severe or significant liver disease, defined as any of the following: acute viral hepatitis; chronic active hepatitis; chronic active hepatitis; cirrhosis; or elevated biochemical function markers i.e. alt or ast >3x the uln or egfr <30ml/min/1.73m2 - creatine kinase (ck) levels > 2x upper limit of normal (uln) - female of child-bearing potential that is unable or unwilling to use reliable method of contraception, breastfeeding, or planning a pregnancy - for a sub-group of participants undergoing mri - any contraindication to mri due to metallic body parts or claustrophobia - medical history of a disorder that might, in the opinion of the attending clinician, put the participant at significant risk if they were to participate in the trial