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Homocysteinemia: new information about an old risk factor for vascular disease
1Lincoln National Re, Fort Wayne, IN 46804, USA.
Insights
Elevated homocysteine levels (homocysteinemia) are a significant risk factor for premature vascular diseases, including heart attack and stroke. Vitamin supplementation may lower homocysteine but its effectiveness in preventing vascular disease requires further study.
Area of Science:
- Cardiovascular Medicine
- Biochemistry
- Genetics
Background:
- Homocysteine, a methionine metabolite, is linked to vascular disease.
- Genetic and nutritional factors influence homocysteine levels.
- Elevated homocysteine is associated with increased risk of various vascular conditions.
Purpose of the Study:
- To evaluate the role of homocysteinemia as a risk factor for atherosclerotic vascular disease.
- To review existing literature on the association between homocysteine and vascular pathology.
Main Methods:
- A comprehensive literature review was conducted.
- MEDLINE database search (1969-1998) using keywords 'homocysteine' and 'vascular disease'.
- 13 relevant articles were selected for detailed analysis.
Main Results:
- Homocysteinemia, from inherited or acquired causes (e.g., vitamin deficiencies, MTHFR gene mutation), significantly increases the risk of coronary artery disease, peripheral artery disease, stroke, and venous thrombosis.
- The risk associated with homocysteinemia is comparable to that of hyperlipidemia and tobacco use.
- Mechanisms linking homocysteine to vascular damage are discussed.
Conclusions:
- Homocysteinemia is established as a risk factor for premature vascular disease.
- While vitamin supplementation (folic acid, B12, B6) can lower homocysteine levels, its efficacy in preventing or treating vascular disease progression is not yet definitively proven.
Objective:
To determine the importance of homocysteinemia as a risk factor for atherosclerotic vascular disease.
Design:
Literature review of published studies homocysteine as risk factor for atherosclerotic vascular disease.
Methods:
MEDLINE search from 1969 to 1998 using homocysteine and vascular disease as search terms, from which 13 articles were selected for review.
Results:
Homocysteine is a sulfur containing amino acid derivative formed during methionine metabolism. Inherited deficiencies of cystathionine B synthase or MTHF reductase result in markedly elevated plasma homocysteine levels and homocystinuria. Although rare, hereditary homocystinuria results in a variety of life threatening vascular complications occurring at a young age. Lesser degrees of homocysteinemia may result from vitamin B12, folate and pyridoxine deficiencies as well as a recently described mutation of the MTHF reductase gene. Homocysteinemia from these causes has been shown to increase the risk of coronary artery disease, peripheral artery disease, stroke, and venous thrombosis. Postulated mechanisms for this association are discussed.
Conclusion:
Homocysteinemia is a risk factor for premature vascular disease. The strength of this association is similar to that due to hyperlipidemia and tobacco use. Although vitamin supplementation with folic acid, B12, and B6 is able to reduce homocysteine levels in many persons, proof of the effectiveness of vitamin treatment in preventing or halting the progression of vascular disease is not yet available.