Homocysteine and Dementia: An International Consensus Statement.
Level 5 - mechanism / opinion, no new human data
International consensus statement and expert narrative review.
PubMed 29480200 · doi:10.3233/JAD-171042
What was done
An international expert panel evaluated literature from the preceding 20 years examining plasma total homocysteine (tHcy) and B-vitamin status (folate, B12, B6) in relation to cognitive decline, dementia, and Alzheimer's disease, applying the Bradford Hill criteria for causation.
What was found
The panel reported that across clinical studies, moderately elevated tHcy (within normal range or >11 µmol/L) was associated with a relative risk of dementia ranging from 1.15 to 2.5 and a population attributable risk between 4.3% and 31%. The authors noted that B-vitamin intervention trials in older adults with cognitive impairment markedly slowed both whole and regional brain atrophy rates and cognitive decline.
Why it matters
It articulates an international expert consensus that elevated homocysteine is a modifiable risk factor for dementia that is safe, inexpensive, and feasible to address with B vitamins.
Limits
As a consensus statement, it reflects expert synthesis rather than a formal systematic review or meta-analysis. The abstract does not specify the exact number of studies reviewed, pooled sample sizes, or confidence intervals. Further randomized trials are still needed to determine if treatment prevents conversion to dementia.
Cited by
- supports Elevated blood homocysteine increases risk for cognitive decline and dementia at levels above 13 micromol/L, with elevated risk likely starting above 10 to 11 micromol/L.