Compared with subjects who took placebo pills, those who took daily supplements of the antioxidant vitamin E and were followed for an average of two years and three months delayed their loss of function by a little over six months on average, a 19% improvement. And the vitamin E group's increased need for caregiver help was the lowest of several groups, including those taking the Alzheimer's drug memantine, those taking memantine and vitamin E, and those taking a placebo pill.
The new research, published Tuesday in the Journal of the American Medical Assn. (JAMA), also cast doubt on earlier findings suggesting that vitamin E supplements hastened death in those with Alzheimer's. The study found that subjects taking vitamin E were no more likely to die of any cause during the study period than those taking memantine or a placebo.
The findings offer a slim ray of hope that the progressive memory loss and mental confusion that characterizes Alzheimer's can at least be slowed by an agent that is inexpensive and easily accessible. Far more expensive drugs that come with greater risks and more side effects have failed to do as well in altering the trajectory of the disease.
The authors of the study called the outcomes seen among those who took vitamin E "a meaningful treatment effect" that was on a par with those seen in clinical trials of prescription drugs approved by the Food and Drug Administration. They expressed surprise that those taking memantine along with vitamin E did not show a delay in functional loss. Possibly, the researchers noted, memantine may disrupt or hinder the metabolism or absorption of vitamin E.
"For people who are in the early stage of Alzheimer's disease, I think any delay in the rate of progression is meaningful and important," said Maurice W. Dysken, the study's lead author.
While memantine has shown itself effective in slowing loss of function among patients with moderate to severe Alzheimer's, its effectiveness in earlier stages of the disease has been less well explored.
In an accompanying editorial in JAMA, Dr. Denis A. Evans, a neurologist at Rush University Medical Center, called the effects of vitamin E "modest" in that it appeared to ameliorate symptoms rather than disrupt or reverse the inexorable march of the disease. Given the expected swelling numbers of those at risk and the discouraging record of progress in finding therapies that could reverse or cure Alzheimer's, Evans wrote, a shift in emphasis toward the prevention "seems warranted."
The study is one of the largest and longest to track participants with mild to moderate Alzheimer's. It followed 561 patients, 97% of them men, from 14 Veterans Affairs medical centers around the country. Researchers tracked each subject for as little as six months and as long as four years after diagnosis with possible or probable Alzheimer's disease of mild to moderate severity.
Subjects were assigned randomly to one of four groups: 139 subjects got a hard-gelatin, liquid-filled capsule of 200 IUs of DL-alpha-tocopherol acetate ("synthetic" vitamin E) and a maintenance dose of 10 mg. of memantine; 140 got the vitamin E capsule and a memantine placebo; 142 got a placebo vitamin E capsule and memantine; and 140 got placebo vitamin E and placebo memantine.
Using a 78-point inventory of "activities of daily living," researchers evaluated subjects' function every six months, and asked caregivers to report on dementia-related behavioral problems and how much assistance the subjects needed in six major areas of activity. They also assessed subjects' memory, language, gait and general mental function.
While subjects on memantine and those on the placebo required increased caregiver assistance ranging from 2.2% to 2.43% annually, caregivers of those taking vitamin E reported their time spent assisting the patient increased annually by 1.48%.
(Source: latimes.com)
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