Coronary Heart Disease
Low circulating folate and vitamin B6 concentrations: risk factors for
stroke, peripheral vascular disease, and coronary artery disease. European
Robinson K; Arheart K; Refsum H; Brattstrom L; Boers G; Ueland P;
Rubba P; Palma-Reis R; Meleady R; Daly L; Witteman J; Graham I
Circulation 1998 Feb 10;97(5):437-43
BACKGROUND: A high plasma homocysteine concentration is a risk factor
for atherosclerosis, and circulating concentrations of homocysteine are
related to levels of folate and vitamin B6. This study was performed to
explore the interrelationships between homocysteine, B vitamins, and vascular
diseases and to evaluate the role of these vitamins as risk factors for
atherosclerosis. METHODS: In a multicenter case-control study in Europe,
750 patients with documented vascular disease and 800 control subjects
frequency-matched for age and sex were compared. Plasma levels of total
homocysteine (before and after methionine loading) were determined, as
were those of red cell folate, vitamin B12, and vitamin B6. RESULTS: In
a conditional logistic regression model, homocysteine concentrations greater
than the 80th percentile for control subjects either fasting (12.1 micromol/L)
or after a methionine load (38.0 micromol/L) were associated with an elevated
risk of vascular disease independent of all traditional risk factors.
In addition, concentrations of red cell folate below the lowest 10th percentile
(<513 nmol/L) and concentrations of vitamin B6 below the lowest 20th
percentile (<23.3 nmol/L) for control subjects were also associated
with increased risk. This risk was independent of conventional risk factors
and for folate was explained in part by increased homocysteine levels.
In contrast, the relationship between vitamin B6 and atherosclerosis was
independent of homocysteine levels both before and after methionine loading.
CONCLUSIONS: Lower levels of folate and vitamin B6 confer an increased
risk of atherosclerosis. Clinical trials are now required to evaluate
the effect of treatment with these vitamins in the primary and secondary
prevention of vascular diseases.