Homocysteine as a biomarker for cognitive dysfunction in the elderly

Homocysteine and B vitamins have been investigated in association with cognitive dysfunction in healthy and in multimorbid elderly patients. Whether reduction of hyperhomocystemia is reducing the risk of dementia or Alzheimer's disease is still under investigation.

High homocysteine concentrations are associated with poorer cognitive function but can be influenced by a number of factors. The results of epidemiological studies are inconsistent in showing an association between elevated homocysteine levels and dementia or Alzheimer disease. Although prospective studies show a trend towards a benefit of homocysteine-related B vitamin substitution, consistent data are expected from upcoming clinical intervention trials. Data from recent clinical randomized trials including various cognitive tests, different aging groups and supplements in different doses are not sufficient to allow recommendation of homocysteine-reducing therapy with folate or vitamin B12 substitution. According to the published data it remains to be proven whether a reduction in homocysteine will improve cognitive performance.

Homocysteine by itself is not a useful marker for screening cognitive decline, or Alzheimer disease but works as a surrogate parameter for malnutrition and organ insufficiency in the cognitive-declining patient.