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Cholesterol
People who significantly cut their cholesterol levels with statins may raise the
risk of cancer, a study says. The study
of 40,000 people found those with little
of the “bad” cholesterol LDL saw one
more cancer case per 1,000 than those
with higher levels. The Boston-based
researchers could not say if this was a
side-effect of the statin or due to the
low cholesterol. They also write in the
Journal of the American College of
Cardiology that the benefits of statins
outweigh the risks.
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“The analysis doesn’t implicate the
statin in creasing the risk of cancer,”
says lead author Richard Karas of Tufts
University School of Medicine in
Boston. “The demonstrated benefits of
statins in lowering the risk of heart disease remain clear. However certain
aspects of lowering LDL with statins
remain controlversial and merit further
research.” Researchers looked at the
summary data from 13 trials of people
taking statins—a total of 41,173
patients. These findings do not change
the message that the benefits of taking
statins greatly outweigh any potential
risks. British Heart Foundation examined the relationship between low,
medium and high doses of statins and
rates of newly diagnosed cancer.
Higher rates of the disease—which
were not of any type or location—were
observed in the group with the lower
levels. The authors noted their findings
were particularly important at a time
when more and more trials show
significant reductions in LDL levels can
greatly benefit cardiovascular health.
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Cancer information officer Dr. Alison
Ross said: “The findings of this study
should be treated with caution—it is
based on summary data from previous
trials and, as the authors point out
themselves, it does not prove that low
LDL cholesterol levels can increase
cancer risk. Much more research is
needed before any firm conclusions
can be made.” The British Heart Foundation said they had long known of a
relationship between low cholesterol
and cancer. “While this highlights an
association between low levels of LDL
and cancer, this is not the same as
saying that low LDL or statin use
increases the risk of cancer,” said June
Davison, cardiac nurse. “There is overwhelming evidence that lowering LDL
cholesterol through statins saves lives
by preventing heart attacks and
strokes. These findings do not change
the message that the benefits of taking
statins greatly outweigh any potential
risks.”
A major international trial has been set
up to see whether a treatment to
increase so-called “good” cholesterol
can prevent heart attacks and strokes.
“Good” cholesterol—high density lipoproteins (HDL)—cuts heart disease risk
by removing fat from the circulation.
The treatment, designed to increase
levels of HDL, will be given alongside
drugs to reduce “bad” cholesterol,
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alongside drugs to reduce “bad” cholesterol, which can raise the risk of disease. A team at Oxford University is
leading the trial involving 20,000 volunteers. To be eligible for the trial,
patients must be aged between 50 and
80 with a history of heart attack, stroke
or peripheral artery disease. Around
7,500 men and women will be recruited
from the UK with people from China
and Scandinavia making up the rest of
the participants. The main ingredient in
the trial drug is niacin, which has been
found to increase levels of HDL by
between a fifth and a quarter as well as
decreasing dangerous fatty substances
called triglycerides. “The trial will be in
people at risk of future heart problems
despite the fact that their LDL cholesterol has been lowered,” said Dr. Jane
Armitage, trial leader.
But patients have found it difficult to
take niacin long-term because it produces an uncomfortable side-effect of
flushing. To combat this effect, niacin
has been combined with another drug,
which blocks the release of prostaglandin D2—the substance which
produces the flushing effect. The team
at the Clinical Trials Unit at Oxford previously carried out the landmark Heart
Protection Study which showed a third
of all heart attacks and strokes could be
avoided in people at risk of vascular
disease by using statins to lower “bad”
cholesterol or low density lipoproteins
(LDL). Large-scale trials have shown
that lowering LDL for four to five years
cuts the risk of heart attacks and stroke
by a quarter. But the risk among
patients who already have vascular
disease remains high even with the use
of statins and there is limited scope for
reducing LDL much more, so researchers are starting to look at ways of also
increasing HDL.
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Dr. Jane Armitage who is leading the
trial said: “The difficulty has been that
there haven’t been good quality drugs
that raise HDL very much. The trial will
be in people at risk of future heart
problems despite the fact that their LDL
cholesterol has been lowered. If it’s
shown to work, the epidemiology suggests it will be possible for people at
lower risk of heart problems to benefit.”
Professor Gilbert Thompson, a lipidology expert at Imperial College said
treatments which raise HDL were the
“next step” in cholesterol research. “It
seems a perfectly reasonable approach
but it won’t necessarily give you a
straight answer about HDL because
niacin also lowers triglyceride. But it will
be a good trial. Dr. Anthony Wierzbicki,
Chair of Heart UK Scientific Medical
and Research Committee, said looking
for ways of raising HDL in addition to
lowering LDL was the next logical step.
“There are a number of trials looking at
this that are either under way or starting
soon, all following the protocol of adding HDL-raising agents to baseline
statin therapy in a variety of patient
populations.” A group of drugs called
CETP inhibitors have also been shown
to increase levels of “good” cholesterol
and are currently in clinical trials.
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