A full description of recruitment and screening procedures has been reported previously.1 (link),15 (link),16 (link) Briefly, participants were recruited from September 2000 to May 2002 from 4 US communities: Hagerstown, Maryland; Pittsburgh, Pennsylvania; Sacramento, California; and Winston-Salem and Greensboro, North Carolina. Participants were required to identify a proxy willing to be interviewed at 6-month study visits. Written informed consent was obtained from participants and their proxies.
Individuals with prevalent dementia meeting Diagnostic and Statistical Manual of Mental Disorders (Fourth Edition)17 criteria for dementia or a score greater than 0.5 on the Clinical Dementia Rating (CDR) scale18 (link) were excluded from participation. Also excluded were individuals meeting any of the following criteria: (1) currently taking warfarin; (2) taking cholinesterase inhibitors for cognitive problems or dementia (memantine had not been approved for use in the United States when the study began); (3) unwilling to discontinue over-the-counter G biloba for the duration of the study; (4) current treatment with tricyclic anti-depressants, antipsychotics, or other medications with significant psychotropic or central cholinergic effects; (5) daily use of more than 400 IU of vitamin E or unwillingness to reduce in-take to this level; (6) history of bleeding disorders; (7) hospitalization for depression within the last year or electroconvulsive therapy within the last 10 years; (8) diagnosis of Parkinson disease or taking anti-Parkinson medications; (9) abnormal thyroid, serum creatinine, or liver function test results; (10) low baseline vitamin B12 levels; (11) low hematocrit level; (12) low platelet count; (13) disease-limited life expectancy of less than 5 years; or (14) known allergy to G biloba.
Participants with MCI at baseline were not excluded. Criteria for MCI at baseline were based on published consensus guidelines.19 (link) In brief, participants were defined as having MCI if they had: (1) impairments at or below the 10th percentile of Cardiovascular Health Study normative data, stratified by age and education, on at least 2 of 10 selected neuropsychological test scores from 5 cognitive domains; and (2) a CDR global score of 0.5.20 (link)
Individuals with prevalent dementia meeting Diagnostic and Statistical Manual of Mental Disorders (Fourth Edition)17 criteria for dementia or a score greater than 0.5 on the Clinical Dementia Rating (CDR) scale18 (link) were excluded from participation. Also excluded were individuals meeting any of the following criteria: (1) currently taking warfarin; (2) taking cholinesterase inhibitors for cognitive problems or dementia (memantine had not been approved for use in the United States when the study began); (3) unwilling to discontinue over-the-counter G biloba for the duration of the study; (4) current treatment with tricyclic anti-depressants, antipsychotics, or other medications with significant psychotropic or central cholinergic effects; (5) daily use of more than 400 IU of vitamin E or unwillingness to reduce in-take to this level; (6) history of bleeding disorders; (7) hospitalization for depression within the last year or electroconvulsive therapy within the last 10 years; (8) diagnosis of Parkinson disease or taking anti-Parkinson medications; (9) abnormal thyroid, serum creatinine, or liver function test results; (10) low baseline vitamin B12 levels; (11) low hematocrit level; (12) low platelet count; (13) disease-limited life expectancy of less than 5 years; or (14) known allergy to G biloba.
Participants with MCI at baseline were not excluded. Criteria for MCI at baseline were based on published consensus guidelines.19 (link) In brief, participants were defined as having MCI if they had: (1) impairments at or below the 10th percentile of Cardiovascular Health Study normative data, stratified by age and education, on at least 2 of 10 selected neuropsychological test scores from 5 cognitive domains; and (2) a CDR global score of 0.5.20 (link)
