High-dose vitamin therapies fail to reduce incidence of stroke
A study designed to find out if vitamin therapy reduces the incidence of stroke in patients with high homocysteine levels has failed to reveal an effect.
Previous research has shown that raised levels of homocysteine are linked
with an increased risk of stroke and heart disease. Because folic acid,
vitamin B6 and vitamin B12 reduce plasma homocysteine levels, US researchers
decided to test whether high doses of these vitamins would reduce the
risk of recurrent stroke.
They assigned 3,680 patients who had previously experienced a stroke
to receive once-daily doses of either a high- or low-dose multivitamin
(25mg vitamin B6, 0.4mg vitamin B12 and 2.5mg folic acid, or 200µg
vitamin B6, 6µg vitamin B12 and 20µg folic acid, respectively).
The researchers found that plasma homocysteine levels were reduced more
among patients given the high-dose
vitamins than among patients given the low-dose vitamins.
However, the chance of a vascular event within two years was similar
for both groups (18.0 per cent compared with 18.6 per cent) (JAMA 2004;291:565). |
The
Pharmaceutical Journal