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  Vol. 301 No. 10, March 11, 2009 TABLE OF CONTENTS
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High-Dose B Vitamin Supplements and Alzheimer Disease—Reply

Since this article does not have an abstract, we have provided the first 150 words of the full text and any section headings.

In Reply: Dr Pratico notes that homocysteine levels in the study participants were generally in the normal range. He further states that homocysteine is not a risk factor for dementia unless levels rise above 15 µmol/L. Evidence from the US population, however, suggests that the association with dementia is not based on a threshold effect.1 We therefore hypothesized that reduction of homocysteine in individuals without elevated levels would be therapeutic, although our trial results refuted this idea. Pratico makes the interesting point that it is possible that reduction of normal levels could impair homocysteine-dependent metabolic processes. We found no positive or negative effect of high-dose vitamin treatment on cognition in participants in the highest baseline homocysteine quartile (mean [SD], 13.42 [2.45] µmol/L) or lowest baseline quartile (5.66 [0.86] µmol/L). Within the highest quartile, 16 of 94 participants (17%) had baseline homocysteine levels above 15 µmol/L; 14 of these were assigned . . . [Full Text of this Article]

Paul S. Aisen, MD
paisen@ucsd.edu
Department of Neurosciences
University of California, San Diego

Lon S. Schneider, MD, MS
University of Southern California
Los Angeles

Mary Sano, PhD
Mount Sinai School of Medicine
Bronx, New York



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RELATED LETTERS

High-Dose B Vitamin Supplements and Alzheimer Disease
Domenico Pratico
JAMA. 2009;301(10):1020-1021.
EXTRACT | FULL TEXT  

High-Dose B Vitamin Supplements and Alzheimer Disease
Bennett I. Machanic
JAMA. 2009;301(10):1021.
EXTRACT | FULL TEXT  






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