Study designs of evaluations included in the review
Studies were included if they reported relative risks (RRs) or odds ratios (ORs), or provided sufficient data to calculate them. No further study design criteria were applied.
Specific interventions included in the review
Studies were included in the review if they described therapy with statins or other LLDs. Details of the specific drugs used in the included trials were not given.
Participants included in the review
The authors did not specify any selection criteria based on participant characteristics. The populations in the included studies were: African-Americans, California residents, UK residents, older adults across Canada, older adults in Pennsylvania, postmenopausal women, and older adults in Illinois and Arizona.
Outcomes assessed in the review
Studies were included if they provided data on Alzheimer's disease, dementia, or cognitive dysfunction. Alzheimer's disease was diagnosed in the selected studies on the basis of the Mini-Mental State Examination, clinical examination, or ICD-9 codes.
How were decisions on the relevance of primary studies made?
Two authors reviewed all studies and any discrepancies were resolved by a third.