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Contact: amurphy@acc.org;
202-375-6476
July 24, 2007
Study Finds Association Between Low
Cholesterol Levels and Cancer
Benefits of Statin Therapy Outweigh Potential Small Risk
Millions of Americans take statins to lower
their cholesterol, but how low should you go? Many scientific
studies support the benefits of lowering low-density lipoprotein
(LDL) cholesterol, and achieving low LDL cholesterol levels
is one of the most important steps in preventing heart disease.
New research, however, provides evidence for an association
between low LDL levels and cancer risk.
The authors of the study, published in the July
31, 2007, issue of the Journal of the American College
of Cardiology (JACC), set out to understand
how and why statins cause side effects, particularly damage
to the liver and muscle cells. The study findings support
taking multiple medications rather than high-dose statins
to minimize those side effects. The researchers did not expect
to find the increased cancer risk (one additional incident
per 1,000 patients) from low LDL levels, and additional studies
have already begun to investigate this potential risk further.
A key component in future studies will be to confirm the risk
and to identify whether the risk may be a side effect of statins
or just low LDL.
“This analysis doesn’t implicate
the statin in increasing the risk of cancer,” said lead
author Richard H. Karas, M.D., F.A.C.C., professor of medicine
at Tufts University School of Medicine. “The demonstrated
benefits of statins in lowering the risk of heart disease
remain clear; however, certain aspects of lowering LDL with
statins remain controversial and merit further research.”
The researchers found one additional incident
of cancer per 1,000 patients with low LDL levels when compared
to patients with higher LDL levels. In their evaluation of
randomized controlled statin trials published before November
2005, the researchers looked at 13 treatment arms consisting
of 41,173 patients.
Researchers assessed absolute change and percentage
of change in LDL reduction and the resulting achieved LDL
levels in relation to rates of newly diagnosed cancer in each
treatment arm. They also looked at the relationship between
low, intermediate and high doses of statins and rates of newly
diagnosed cancer. Although they did not find a relationship
between percent of change and absolute change in LDL levels,
they observed higher rates of newly diagnosed cancer among
patients with lower achieved LDL levels. In addition, the
new cancers were not of any specific type or location.
Recent data from large-scale statin trials have shown that
more intensive LDL lowering can provide significant cardiovascular
benefits to higher-risk patients. In response to these findings,
recent national guidelines have advocated for lower LDL goals
and higher doses of statins to reach them. However, informal
observations linking intensive LDL lowering and higher incidence
of reported health problems, including liver and muscle toxicity
and cancer, has introduced some concern over the safety of
such treatments.
These concerns in part prompted the current
study. However, the current findings are not definitive, as
limitations of the study show. Researchers performed their
analysis from summary data taken directly from published manuscripts
of each trial. An analysis based on data for each individual
patient would have yielded more specific and potentially more
compelling results, said Dr. Karas.
“These current findings provide insufficient
evidence that there is any problem with LDL lowering that
outweighs its significant benefits on vascular disease,”
said John C. La Rosa, M.D., who wrote an accompanying editorial
in the July 31 issue of JACC. However, “we
must continue to be vigilant in ensuring that its benefit
clearly outweighs its risk.”
Although the cancer risk was surprising, the
researchers primarily sought to determine how and why statins
cause side effects, particularly damage to the liver and muscle
cells. For this portion of the study, researchers analyzed
23 statin treatment arms that included 75,317 patients with
a combined 309,506 years of follow up. A link between LDL
lowering and liver or muscle irritation was not found. However,
liver toxicity levels increased with higher statin dosage.
Based on their findings, the researchers concluded that moderate-dose
therapy with multiple medications including statins may prove
to be preferable to high-dose therapy with statins alone.
Dr. Karas emphasized that patients are advised to continue
their statin treatments and, as always, consult their doctor
before discontinuing use of any medication.
“While these results raise important new
questions about statin use, they do not demonstrate a causal
relationship between statins and cancer,” said James
Dove, M.D., F.A.C.C., president of the American College of
Cardiology. “This study is hypothesis-generating, not
hypothesis-proving.”
The American College of Cardiology is leading the way to
optimal cardiovascular care and disease prevention. The College
is a 34,000-member nonprofit medical society and bestows the
credential Fellow of the American College of Cardiology upon
physicians who meet its stringent qualifications. The College
is a leader in the formulation of health policy, standards
and guidelines, and is a staunch supporter of cardiovascular
research. The ACC provides professional education and operates
national registries for the measurement and improvement of
quality care. More information about the association is available
online at www.acc.org.
The American College of Cardiology (ACC) provides these news
reports of clinical studies published in the Journal of
the American College of Cardiology as a service to physicians,
the media, the public and other interested parties. However,
statements or opinions expressed in these reports reflect
the view of the author(s) and do not represent official policy
of the ACC unless stated so.
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