By Sarah Roberts
Apr 18, 2005, 23:10
A new study found that vitamin E supplements are ineffective in delaying the onset of Alzheimer's disease in people with mild cognitive impairment or "M.C.I.", while a drug called Aricept may delay the progression of MCI into Alzheimer's disease in certain patients.
The study involved 769 patients with mild M.C.I., which often leads to Alzheimer's disease. Patients in three groups were assigned either Aricept, vitamin E, or a placebo, and then followed up for a period of three years.
It was found that at the end of first year, the group of patients receiving Aricept significantly reduced the odds of having Alzheimer's. The number of patients that had Alzheimer's was 16 in the Aricept group, 38 in the placebo group and 23 in the vitamin E group.
However, neither Aricept nor vitamin E showed any benefit at the end of the three-year follow-up. Aricept was more effective in a subgroup of patients who carried apolipoprotein 4 alllel, or Apo E4, a genetic risk for Alzheimer's.
The study showed that patients in this subgroup who took Aricept reduced the risk of Alzheimer's by one-third. Three-quarters of patients who had Alzheimer's disease carried this gene.
While the evidence is not strong enough to recommend use of Aricept to prevent Alzheimer's disease, it's clear that vitamin E can't slow the progress of M.C.I. into Alzheimer's.
According to the New York Times, the research was half funded by the National Institute on Aging, and half by Eisai and Pfizer, which manufactures and markets Aricept. Six out of fourteen researchers have received grants or consulting fees from either Esai or Pfizer or both.
The study appeared this week in the New England Journal of Medicine.