Vitamin B May Not Guard Against Second Stroke, Heart
TUESDAY, Aug. 3 (HealthDay News) -- Stroke patients who take
vitamin B supplements to lower their homocysteine levels may not be
protected from second strokes or heart attacks, a new study
Earlier studies found an association between homocysteine, an
amino acid, in the blood, and an increased risk for stroke and
heart attack. Vitamin B supplements lower homocysteine levels, but
whether this really has an effect on stroke and heart attack risk
has been unclear, the Australian researchers noted.
"B vitamins are safe, but they were not, statistically, significantly more effective than placebo in preventing major vascular events among stroke and TIA [transient ischemic attack] patients," said lead researcher Dr. Graeme J. Hankey, head of the stroke unit at Royal Perth Hospital in Western Australia. "B vitamins have not been proven to have a role in secondary stroke prevention."
The report is published in the Aug. 4 online edition of
The Lancet Neurology, and will appear in the September print issue of the journal.
For the study, Hankey and his colleagues in the Vitamins to
Prevent Stroke (VITATOPS) trial tested whether lowering
homocysteine with a combination of folic acid, vitamin B6 and
vitamin B12 would lower the risk of a second stroke or heart attack
in patients who had a recent stroke or transient ischemic
In the trial, 8,164 patients were randomly assigned to daily
doses of either B vitamins or a placebo in addition to standard
Over 3.4 years of follow-up, the researchers found the vitamins
were no more effective than placebo. In all, 15 percent of the
people taking B vitamins had a second stroke, heart attack or died,
compared with 17 percent of those receiving placebo. B vitamins
did, however, lower homocysteine levels.
People taking the vitamins had no adverse reactions and the
vitamins were well-tolerated, the researchers noted.
Despite these findings, Hankey isn't sure that B vitamins don't
work. "Our study may well have been underpowered statistically," he
Had the trial gone on longer, a "significant treatment effect
may have emerged, and has thus been missed in our study," Hankey
"I don't think it is the end of the road for B vitamins in stroke prevention. We need to see the effect of B vitamins in the three other ongoing trials, particularly in patients who have been treated for several years, and particularly in patients with stroke caused by small vessel intracranial disease," he added.
Dr. Larry B. Goldstein, director of the Duke Stroke Center at
Duke University Medical Center, agreed that the question of whether
or not B vitamins lower the risk of a second stroke or heart attack
was not answered fully by this trial.
"High homocysteine is associated with both stroke and coronary heart disease. Homocysteine can be lowered with B-complex vitamin supplements, but whether doing so lowers the risk of vascular events is uncertain," Goldstein said.
Earlier studies found no benefit of homocysteine lowering in
subjects with coronary heart disease or renal failure. "The VISP
trial, conducted in North America, found no benefit of B-vitamin
treatment in subjects with prior stroke, but had several important
methodological limitations," Goldstein added.
This new report also finds no benefit of treatment with
B-complex vitamins in patients with stroke or TIA, but the adverse
event rates in both the treatment and placebo groups were lower
than anticipated, he pointed out.
"A benefit by as much as an 18 percent reduction in risk remains possible," Goldstein said. "Treatment with B vitamins appeared safe, and the results of other ongoing trials should help more definitively answer the question."
For more information on stroke, visit the
U.S. National Library of Medicine.
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