Women’s Health Study
Finds Vitamin E does not Protect Women from Heart
Attack, Stroke, or Cancer
Vitamin E supplements do not protect healthy women
against heart attacks and stroke, according to new
results from the Women’s Health Study, a long-term
clinical trial of the effect of vitamin E and aspirin
on both the prevention of cardiovascular disease and
of cancer.
The vitamin E results of the Women’s Health
Study are published in the July 6 issue of the Journal
of the American Medical Association. In addition
to the cardiovascular disease findings, the study
authors report that there was no effect of vitamin
E on total cancer or on the most common cancers in
women – breast, lung, and colon cancers. The
Women’s Health Study was funded by the National
Heart, Lung, and Blood Institute (NHLBI) and the National
Cancer Institute of the National Institutes of Health.
“This landmark trial has given women and their
physicians important health information. We can now
say that despite their initial promise, vitamin E
supplements do not prevent heart attack and stroke.
Instead, women should focus on well proven means of
heart disease prevention, including leading a healthy
lifestyle and controlling risk factors such as high
blood pressure and high cholesterol,” said NHLBI
Director Elizabeth G. Nabel, M.D.
The Women’s Health Study was conducted between
1992 and 2004. The participants were 39,876 healthy
women age 45 years and older who were randomly assigned
to receive 600 IU of Vitamin E or placebo and low-dose
aspirin or placebo on alternate days. The participants
were followed for an average of 10.1 years. The aspirin
results published last March found no benefit of aspirin
(100 mg every other day) in preventing first heart
attacks or death from cardiovascular causes in women
but did find a reduced risk of stroke overall, as
well as reduced risk of both stroke and heart attack
in women aged 65 and older.
In recent years, there has been a great deal of public
and scientific interest in the potential of antioxidant
vitamins like vitamin E to reduce the risk of cardiovascular
disease. Laboratory and animal research suggested
that vitamin E might prevent the accumulation of fatty
deposits inside arteries, which would reduce the chance
of clogged and blocked arteries. Other large observational
studies have also suggested that people who eat foods
high in vitamin E or take supplements have a lower
risk of coronary heart disease. Although several clinical
trials conducted prior to the Women’s Health
study found little cardiovascular benefit from vitamin
E, these trials were shorter and primarily studied
individuals with cardiovascular disease or CVD risk
factors. The intent of the Women’s Health Study
was to provide a long-term look at the effects of
vitamin E supplementation among healthy women.
Participants in the Women’s Health Study were
monitored for major cardiovascular “events”
– a combination of nonfatal heart attack, nonfatal
stroke, or cardiovascular death. By the end of the
study, participants in the vitamin E group had 482
such events compared to 517 in the placebo group.
However, this difference was not statistically different.
For the individual cardiovascular events, the study
findings were:
- Nonfatal heart attacks: 184 in the vitamin E
group versus 181 in the placebo group –
not a statistically significant difference.
- Nonfatal strokes: 220 in the vitamin E group
versus 222 in the placebo group – not statistically
significant.
Study investigators also found no significant effect
of vitamin E on total deaths (deaths from all causes).
By the end of the study, there were 636 deaths in
the vitamin E group compared to 615 in the placebo
group.
Although total deaths were unaffected by vitamin E,
there was a significant 24 percent reduction in cardiovascular
deaths among all women taking the vitamin (106 deaths
in the vitamin E group versus 140 in the placebo group).
In another positive finding, women 65 and older taking
vitamin E had a 26 percent decrease in heart attacks
and cardiovascular deaths, but not strokes.
“These intriguing findings deserve further study.
But they were not part of the primary aim of the study
– to look at the effect of vitamin E on overall
cardiovascular disease, which includes heart attack,
stroke, and cardiovascular death. Additionally, previous
studies of vitamin E in patients with heart disease
have not shown any benefit for cardiovascular deaths.
At present, we cannot recommend vitamin E for prevention
against cardiovascular disease or cancer,” said
lead investigator I-Min Lee, MBBS, ScD of Brigham
and Women’s Hospital.
The study finding of a decrease in major cardiovascular
events among women age 65 years and older is relatively
unique, added Dr. Lee. “Almost all previous
trials have not reported findings by age. If other
current trials provide age-related results, these
additional data will help clarify the Women’s
Health Study results of benefit among the women aged
65 years and older,” she said.
Overall, the results were not affected by a study
participant’s menopausal status, use of hormone
therapy, body mass index, alcohol intake, or physical
activity. The study found no significant side effects
among women taking vitamin E except for an increase
in nosebleeds, which was likely due to chance, as
there was no increase in risk of other types of bleeding,
including hemorrhagic stroke.
According to the 1999-2000 National Health and Nutrition
Examination Survey, an estimated 13.5 percent of women
in the U.S. take vitamin E supplements, although it
is not known how many are taking the vitamin to prevent
heart disease and stroke.
NHLBI’s Dr. Nabel encouraged women to learn
more about proven ways to prevent heart disease, the
number one killer of women. The Heart Truth (www.hearttruth.gov.),
NHLBI’s program to increase women’s awareness
of the dangers of heart disease, offers resources
and information on leading a healthy lifestyle.
To interview an NHLBI spokesperson about the Women’s
Health Study findings, contact the NHLBI Communications
Office at (301) 496-4236. To interview a study investigator,
contact Melanie Franco or Lori Shanks at Brigham and
Women’s Hospital at (617) 534-1600.
NHLBI is part of the National Institutes of Health
(NIH), the Federal Government’s primary agency
for biomedical and behavioral research. NIH is a component
of the U.S. Department of Health and Human Services.
NHLBI press releases and other materials including
information about high blood pressure and heart disease
are available online at www.nhlbi.nih.gov.
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