The daily dosage of 2,000 IUs also proved effective in reducing caregiver time in assisting patients, according to the study, which appeared in the Journal of the American Medical Association (JAMA).
Alpha tocopherol, a fat-soluble vitamin (E) and antioxidant, has been studied in patients with moderately severe Alzheimer disease (AD) and in patients with mild cognitive impairment (MCI). But it has yet to be studied in patients with mild to moderate Alzheimer’s, the researchers note.
In patients with moderately severe AD, Vitamin E was shown to be effective in slowing clinical progression.
The drug memantine also has been shown to be effective in patients with AD and moderately severe dementia, according to background information in the study.
This led Maurice W. Dysken, M.D., of the Minneapolis VA Health Care System, and his colleagues to examine the effectiveness and safety of Vitamin E, memantine, and the combination for treatment of functional decline in patients with mild to moderate AD who were taking an acetylcholinesterase inhibitor (a chemical that increases the level and duration of action of the neurotransmitter acetylcholine).
The trial included 613 patients at 14 Veterans Affairs medical centers. The patients were split into four groups, with one group receiving 2,000 IU/day of Vitamin E, another receiving 20 mg/d of memantine, the third receiving the combination, and the fourth a placebo.
Change in functional decline was gauged via the Alzheimer’s Disease Cooperative Study/Activities of Daily Living (ADCS-ADL) Inventory score (range, 0-78), the researchers explained.
Over the average follow-up time of 2.3 years, patients receiving Vitamin E had slower functional decline than those receiving a placebo, with the annual rate of decline in ADLs reduced by 19 percent, the study found. This translates into a clinically meaningful delay in progression in the Vitamin E group of 6.2 months, the researchers explained.
Neither memantine nor the combination of Vitamin E and memantine showed clinical benefit in this trial, the researchers noted.
In addition, caregiver time was reduced by about two hours a day in the Vitamin E group, according to the study.
The authors write that the current study is one of the largest and longest treatment trials in patients with mild to moderate AD, and that it provides information on reported safety issues of Vitamin E, with results from previous trials resulting in decreased prescribing for patients with AD.
“In contrast to the conclusion drawn from a 2005 meta-analysis of Vitamin E, which showed that high-dose Vitamin E (≥ 400 IU/d) may increase the risk of all-cause mortality, we found no significant increase in mortality with Vitamin E,” the researchers reported.
“The annual mortality rate was [also lower] — 7.3 percent in the alpha tocopherol group vs. 9.4 percent for the placebo group.”
The researchers note that decline in functioning is increasingly recognized as an important determinant of both patient quality of life and social and economic costs.
“In the current study, the placebo group lost approximately three units more on the ADCS-ADL Inventory than the alpha tocopherol group,” the study concludes.
“A loss of this magnitude could translate into either the complete loss of being able to dress or bath independently, for example, or losing independence on any three different ADLs. Because Vitamin E is inexpensive, it is likely these benefits are cost-effective as alpha tocopherol improves functional outcomes and decreases caregiver burden.”
Source: The JAMA Network Journals