There may be a link between low levels of "bad" low-density lipoprotein (LDL) cholesterol and increased cancer risk, according to new research.
In the study, researchers looked at 201 cancer patients and 402 cancer-free patients. They found that cancer patients who never took cholesterol-lowering drugs had low LDL cholesterol levels for an average of about 19 years prior to their cancer diagnosis.
The finding suggests there may be some underlying mechanism that affects both LDL cholesterol levels and cancer risk, the study authors said.
Still, other experts cautioned that the finding is preliminary, and lowering your LDL levels is well known to cut the odds for the number one killer, heart disease.
Previous studies of cholesterol-lowering drugs have suggested a strong link between low LDL cholesterol levels and cancer risk. This new study is the first to investigate the association between low LDL cholesterol levels and cancer risk over an extended period of time only in cancer patients who have never taken cholesterol-lowering medication, the researchers said.
"There has been some debate as to whether or not medications used to lower cholesterol may contribute to cancer, but the evidence so far tells us that the drugs themselves do not increase the risk of cancer. We wanted to take those medications out of the equation and just look at the link between cancer and low LDL cholesterol itself in people who had never taken statins or other cholesterol-lowering drugs," lead investigator Dr. Paul Michael Lavigne of Tufts Medical Center in Boston, said in an ACC news release.
Further testing required
Although the study uncovered an association between low LDL levels and increased cancer risk, it did not prove a cause-and-effect relationship.
A cardiology expert weighed in on the new study.
"I strongly believe that lowering LDL cholesterol significantly lowers the risk of cardiovascular events, but the association between low LDL cholesterol and cancer remains a hypothesis that requires further testing," said Dr Jeffrey Berger, director of cardiovascular thrombosis at NYU Langone Medical Center and an assistant professor at the NYU School of Medicine in New York City.
"The association between low LDL cholesterol and the risk of cancer has become a topic of increasing interest, but conclusions cannot be drawn from this study," Berger added. "The study suggests that there may be some sort of unique attribute among subjects that already have a low LDL cholesterol that may make them susceptible to cancer, but future studies will have to look at why that is."
Study author Lavigne said the findings do not suggest that having low LDL cholesterol somehow leads to the development of cancer, and urged patients with high LDL cholesterol to continue treatment to lower their LDL cholesterol in order to prevent heart disease.
"There is no evidence to indicate that lowering your cholesterol with a medication in any way predisposes to a risk for cancer. We suspect there may be some underlying mechanism affecting both cancer and low LDL cholesterol, but we can only say definitively that the relationship between the two exists for many years prior to cancer diagnosis, and therefore underscores the need for further examination," Lavigne said.
Don't stop statins
Another expert agreed that patients should not abandon cholesterol-lowering lifestyle changes or medications based on the new findings.
Dr. David Friedman, chief of heart failure services at North Shore Plainview Hospital in Plainview, N.Y., said that "statins used for LDL reduction shouldn't be stopped if there is an appropriate use to lower heart disease risk."
Because this study was presented at a medical meeting, the data and conclusions should be viewed as preliminary until published in a peer-reviewed journal.
What do cholesterol levels mean?
The American Heart Association has more about good and bad cholesterol.
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