Lecithin for dementia and cognitive impairment.
BACKGROUND
People with Alzheimer's disease have been found to have a relative lack of the enzyme responsible for converting choline into acetylcholine within the brain. Lecithin is a major dietary source of choline, so extra consumption may assist in the production of acetylcholine and reduce some of the symptoms of dementia.


OBJECTIVE
To determine the efficacy of lecithin in the treatment of dementia or cognitive impairment.


METHODS
The Cochrane Dementia and Cognitive Impairment Group Register of Clinical Trials has been searched, as have the electronic databases MEDLINE, EMBASE, Psychlit, ISI and Current Contents. Reference lists and relevant books have been examined.


METHODS
All unconfounded, randomised trials comparing lecithin with placebo in a treatment period longer than one day, in patients with dementia of the Alzheimer type, vascular dementia, mixed vascular and Alzheimer's disease, unclassified or other dementia or unclassified cognitive impairment not fulfilling the criteria for dementia are eligible for inclusion.


METHODS
Data are extracted by two independent reviewers and cross checked. Meta-analyses are performed when more than one trial provide data on a comparable outcome on sufficiently similar patients. Random effects analyses are performed whenever heterogeneity between results appears to be present. Standardised mean difference are used due do the use of different scales and periods of treatment. Odds ratios for dichotomous data are pooled using the Mantel-Haenszel or DerSimonian and Laird methods.


RESULTS
Eleven randomised trials have been identified involving patients with Alzheimer's disease (265 patients) and Parkinsonian dementia (21 patients). No trials reported any clear clinical benefit of lecithin. Few trials contributed data to meta-analyses. The only statistically significant result was in favour of placebo for adverse events, based on one trial, which appears likely to be a spurious result.


CONCLUSIONS
Evidence from randomised trials does not support the use of lecithin in the treatment of patients with dementia or cognitive impairment. A moderate effect cannot be ruled out, but results from the small trials to date do not indicate priority for a large randomised trial.
Higgins
J P
JP
MRC Biostatistics Unit, Institute of Public Health, Robinson Way, Cambridge, Cambridgeshire, UK, CB2 2SR. julian.higgins@mrc-bsu.cam.ac.uk
Flicker
L
L
D000544:Alzheimer Disease / Q000188:drug therapy; D003072:Cognition Disorders / Q000188:drug therapy*; D003704:Dementia / Q000188:drug therapy*; D006801:Humans; D010713:Phosphatidylcholines / Q000627:therapeutic use*
D010713:Phosphatidylcholines