Gingko biloba does not stop incidence of Alzheimer's disease, Lancet reports

The long-term use of gingko biloba extract does not lower the risk of Alzheimer’s disease, according to a report published September 6 online for The Lancet.

In a randomized, placebo-controlled clinical trial, researchers followed 2,854 patients aged 70 years and older who presented to their primacy care physician (PCP) with memory complaints. Between March 2002 and November 2004, almost half of the patients were randomly assigned to a twice-daily dose of 120 mg of ginkgo biloba extract and the other half received placebo. Patients were followed for 5 years by their PCPs or expert memory centers. The primary end point was the diagnosis of probable Alzheimer’s disease, according to Bruno Vellas, of Toulouse, France, and colleagues.

Patients were assessed for cognitive, functional, and depressive status every year using a series of tests, including MMSE, CDR, FCSRT, trail making test, verbal fluency, visual analogue scales, instrumental activities of daily living, and the geriatric depression scale. Safety of the extract was assessed every 3 months by monitoring vital signs, physical and neurological examinations, and adverse events. The most common reasons for withdrawal from the study were personal reasons, including withdrawal of informed consent, relocation, or change of PCP.

Of the patients who received gingko biloba, 61 of the 1,406 patients were diagnosed with probable Alzheimer’s disease compared with 73 of 1,414 in the placebo group (HR=0.84; 95% CI, 0.60-1.18; P=.306). In the gingko biloba group, incidence of Alzheimer’s disease was 1.2 per 100 person years, and in the placebo group, it was 1.4 per 100 person years.

“Long-term administration of standardized ginkgo biloba extract at 240 mg daily did not affect vital signs, physical function, or neurological function,” the authors reported.

The long-term use of standardized gingko biloba extract for the prevention of Alzheimer’s disease (GuidAge) study was funded by Ipsen, Boulogne, France, which markets the extract, and the French National Association of Technical Research.