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Does raised homocysteine cause dementia? Ho et al., 2011 Am J Geriatr Psychiatry 19:607–617

Paper

 

Does raised homocysteine cause dementia? Ho et al., 2011 Am J Geriatr Psychiatry 19:607–617

Details

In this meta-analysis which pooled studies of a total of 6,000 subjects, researchers concluded that while higher homocysteine levels were found in subjects with both Alzheimer’s and vascular dementia (the two major types of dementia), they assert that a causal relationship (i.e. that high homocysteine is a cause of these diseases) is not supported by the evidence.

Our comment: Emeritus Professor David Smith from Oxford University, who has published many original studies on the subject of homocysteine and cognitive declinemakes the following comment on the study above:

“This is a classic example of a flawed meta-analysis. They found 63 articles that met their original selection criteria, but then excluded 48 of them because they didn’t suit the way they wanted to crunch the numbers! They excluded most of the best studies on this topic. Of the 17 studies they included only 4 were prospective, meaning only 4 took a group of people, measured homocysteine, then tracked them over time to see if their homocysteine level was predictive of memory loss. Of these, one was tiny – 26 people with cognitive decline were involved. That means you end up with far too few participants to get much of a statistical effect. On top of this, one of my studies was included, in which we found having a high homocysteine level increased odds of developing pathologically-confirmed Alzheimer’s by 4.5 times. They incorrectly reported our result as increasing risk by 2 times, inaccurately halving the effect. This is bad science.”

Click here for the abstract