DEMENTIA-CONTROLLING DRUG PLUS VITAMIN E SLOWS ALZHEIMER’S
COLUMBUS, Ohio – Combining vitamin E and a drug used to treat mild to moderate dementia may slow the progression of Alzheimer’s disease, a new study reports.
Researchers at Ohio State University found that after just a year of treatment with vitamin E and the drug donepezil (known by the brand name Aricept), people with Alzheimer’s disease performed much better on tests of cognitive ability than did people who hadn’t taken either substance.
"There were notable cognitive differences even after three years of combined therapy," said David Beversdorf, the study’s senior author and an assistant professor of neurology at Ohio State University. "It slowed down the cognitive decline that characterizes the disease."
Emily Klatte, the study's lead author and currently a resident in Ohio State's department of neurology and Beversdorf and their colleagues studied 40 patients with Alzheimer’s disease who took daily doses of both vitamin E and donepezil. The participants also took a cognitive abilities test each year during the three-year study. Their annual test scores were compared to the scores of Alzheimer’s patients who took the same kind of test prior to 1996 – before donepezil and similar drugs were available, and also before vitamin E was touted as possibly having a role in disease prevention and progression.
The decline in cognitive test scores of patients who had not taken either agent was three times greater after a year than the decline in scores of the patients taking the combined therapy.
The study appears in a recent issue of the journal Alzheimer Disease and Associated Disorders.
Donepezil is one of a family of drugs called cholinesterase inhibitors. These drugs help prevent the breakdown of acetylcholine – a chemical messenger in the brain that transmits information between neurons. Researchers think that the loss of acetylcholine is a major contributor to the development and progression of Alzheimer’s disease. Vitamin E, on the other hand, is thought to slow the progression of dementia by preventing free radical damage in the brain.
"Both treatments are accepted strategies in treating Alzheimer's disease," Beversdorf said. "Because cholinesterase inhibitors and vitamin E work through distinct mechanisms of action, we'd expect to see benefits of combined therapy.
"But no long-term study had ever looked at the combination to see if it indeed helped patients. Such investigation was necessary to be sure that these two agents didn't somehow interfere with each other in the treatment of Alzheimer's disease."
For the retrospective study, the researchers reviewed the medical charts of 40 patients with mild to moderate Alzheimer's disease who had taken a minimum of 1,000 U (about 670 mg) of vitamin E in supplement form and at least 5 mg of donepezil daily for at least a year. The patients had also been given the mini-mental state examination (MMSE) – a test of cognition used to assess dementia in Alzheimer’s patients.
Information on Alzheimer's patients who, for at least three years, had taken either donepezil or vitamin E alone wasn't available. While future prospective studies would benefit from comparing the combined treatment to treatments of either vitamin E or donepezil alone, Beversdorf said that such trials might be difficult to conduct because of the current widespread accepted use of both agents.
The researchers compared the MMSE scores of the people who took the dual treatment to the test scores of Alzheimer’s patients listed in the Consortium to Establish a Registry for Alzheimer’s disease (CERAD) database – a database that includes information on Alzheimer’s patients prior to 1996.
All of the subjects taking vitamin E and donepezil were given the MMSE at the beginning of the study, and again a year later. Thirty-eight subjects were tested after two years of treatment, and 22 participants were re-tested after the third year of treatment. The researchers compared these scores to subjects in the CERAD database who had taken the MMSE test for three continuous years.
After the first year, the decline in test scores of the CERAD group was nearly three times higher than the decline in scores of the treated group. By the study’s third year, the decline in test scores of the CERAD patients was nearly one-and-a-half times higher than the decline in scores of the comparable treated group.
"It appears that long-term treatment with both vitamin E and donepezil has a notable impact on retaining mental function in patients with Alzheimer’s," Beversdorf said.
Klatte and Beversdorf conducted the study with Ohio State colleagues Douglas Scharre, Haikady Nagaraja, and Rebecca Davis.
The research was funded by an unrestricted educational grant from Pfizer/Eisai, the manufacturers of Aricept; Nagaraja's funding came from the National Institutes of Health; and the CERAD database was funded by the NIH National Institute on Aging.