Thiamine for Alzheimer's disease.
BACKGROUND
Vitamin B1 (thiamine) plays an important role in Wernicke-Korsakoff syndrome (a form of amnesia caused by brain damage occurring in long-term alcoholics who rely mainly on alcohol for nutrition). The acute syndrome is normally reversible but may proceed to profound dementia, although its progress can be stopped by a timely injection of a large dose of thiamine. There have been suggestions that thiamine may have a beneficial effect in Alzheimer's disease.


OBJECTIVE
The objective of this systematic review is to evaluate the efficacy of thiamine for people with Alzheimer's disease.


METHODS
The Cochrane Controlled Trials Register (Issue 3:2000), the CDCIG Trials Register and other sources were searched for this update in July 2000 using the terms 'alzheimer*', thiamin* and vitamin B1'. In addition bibliographies of published reviews, and conference proceedings were searched and pharmaceutical companies and trials investigators were contacted.


METHODS
All unconfounded, double-blind, randomized trials in which treatment with thiamine was administered for more than a day and compared with placebo in patients with dementia of the Alzheimer's type.


METHODS
Data were extracted independently by two reviewers and the odds ratios (95% CI) or the average differences (95% CI) were estimated.


RESULTS
There are three included studies, but few results were reported that could be included. The cross-over studies did not report results from the first phase. It was not possible to pool any results for a meta-analysis. Nolan 1991 reports results that show no evidence of an effect on MMSE at 3, 6, 9 and 12 months for thiamine compared with placebo for those who completed the trial. Meador 1993a noted that 3/8 on thiamine compared with 6/9 on placebo were worse as measured on the ADAS-Cog at 3 months compared with baseline, but the difference is not statistically significant. Blass 1988 and Nolan 1991 reported that no significant side-effects were noted during the study, and Meador 1993a did not mention side-effects. Blass 1988 noted that 5/16 and Nolan 1991 that 5/15 did not complete the study, but neither mentioned the groups to which these people belonged.


CONCLUSIONS
It is not possible to draw any conclusions from this review. The number of people included in the studies if less than 50 and the reported results are inadequate.
Rodríguez-Martín
J L
JL
Iberoamerican Cochrane Centre, Department of Epidemiology, Hospital de la Santa Creu i Sant Pau, Sant Antoni M feminine Claret, 171, Barcelona, Catalunya, Spain, 08041. jrodriguezma@hsp.santpau.es
Qizilbash
N
N
López-Arrieta
J M
JM
D000544:Alzheimer Disease / Q000188:drug therapy* / Q000523:psychology; D003072:Cognition Disorders / Q000188:drug therapy; D006801:Humans; D013831:Thiamine / Q000627:therapeutic use*
D013831:Thiamine