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- Clarke, Robert, et al.
(författare)
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Lowering blood homocysteine with folic acid based supplements : Meta-analysis of randomised trials
- 1998
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Ingår i: British Medical Journal. - : BMJ. - 0959-8146. ; 316:7135, s. 894-898
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Forskningsöversikt (refereegranskat)abstract
- Objective: To determine the size of reduction in homocysteine concentrations produced by dietary supplementation with folic acid and with vitamins B-12 or B-6. Design: Meta-analysis of randomised controlled trials that assessed the effects of folic acid based supplements on blood homocysteine concentration. Multivariate regression analysis was used to determine the effects on homocysteine concentrations of different doses of folic acid and of the addition of vitamin B-12 or B-6. Subjects: Individual data on 1114 people included in 12 trials. Findings: The proportional and absolute reductions in blood homocysteine produced by folic acid supplements were greater at higher pretreatment blood homocysteine concentrations (P < 0.001) and at lower pretreatment blood folate concentrations (P < 0.001). After standardisation to pretreatment blood concentrations of homocysteine of 12 μmol/l and of folate of 12 nmol/l (approximate average concentrations for Western populations), dietary folic acid reduced blood homocysteine concentrations by 25% (95% confidence interval 23% to 28%; P < 0.001), with similar effects in the range of 0.5-5 mg folic acid daily. Vitamin B-12 (mean 0.5 mg daily) produced an additional 7% (3% to 10%) reduction in blood homocysteine. Vitamin B-6 (mean 16.5 mg daily) did not have a significant additional effect. Conclusions: Typically in Western populations, daily supplementation with both 0.5-5 mg folic acid and about 0.5 mg vitamin B-12 would be expected to reduce blood homocysteine concentrations by about a quarter to a third (for example, from about 12 μmol/l to 8-9 μmol/l). Large scale randomised trials of such regimens in high risk populations are now needed to determine whether lowering blood homocysteine concentrations reduces the risk of vascular disease.
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| 5. |
- Sundström, Johan, et al.
(författare)
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Relations of plasma homocysteine to left ventricular structure and function : the Framingham Heart Study.
- 2004
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Ingår i: Eur Heart J. - 0195-668X. ; 25:6, s. 523-30
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Tidskriftsartikel (refereegranskat)abstract
- AIMS: Hyperhomocysteinaemia is a risk factor for congestive heart failure, especially in women. We investigated if homocysteine promotes left ventricular (LV) remodelling. METHODS AND RESULTS: We examined cross-sectional relations of plasma total homocysteine to echocardiographic LV structure and function in 2697 Framingham Heart Study participants (mean age 58 years, 58% women) free of heart failure and previous myocardial infarction. Adjusting for age and height, plasma homocysteine was positively related to LV mass, wall thickness, and relative wall thickness in women (p=0.0004-0.04), but not in men (p=0.28-0.68). Adjusting additionally for other clinical covariates, the relations of plasma homocysteine to LV mass and wall thickness in women remained statistically significant, but the relation to relative wall thickness became of borderline significance (1.92 g, 0.01 cm, and 0.29% increase, respectively, for a 1-SD increase in ln[homocysteine], p=0.01-0.08). LV mass and wall thickness were higher in the fourth quartile of plasma homocysteine compared to the lower three in all models in women (p=0.0003-0.02), but not in men (p=0.25-0.78). Plasma homocysteine was not related to left atrial size or LV fractional shortening in either sex. CONCLUSION: In our community-based sample, plasma homocysteine was directly related to LV mass and wall thickness in women but not in men.
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