Low LDL cholesterol in patients with no history of taking cholesterol-lowering drugs predates cancer risk by decades, suggesting there may be some underlying mechanism affecting both cancer and low LDL cholesterol that requires further examination, according to research presented March 25 at the American College of Cardiology's 61st Annual Scientific Session.

While scientific evidence supports the benefits of lowering low-density lipoprotein cholesterol (LDL-C) to help prevent heart disease, previous studies of cholesterol-lowering drugs have suggested a strong association between low levels of LDL-C and cancer risk. This is the first study to examine the relationship of low LDL-C and cancer risk over an extended period of time only in patients with no history of taking cholesterol-lowering drugs.

"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," said Paul Michael Lavigne, MD, resident, Tufts Medical Center and the study's lead investigator.

In a matched case control study, researchers used data from the Framingham Heart Study Offspring Cohort to assess the trend of low LDL-C for an extended period of time prior to cancer diagnosis.

They compared 201 cancer cases and 402 control cases that were cancer-free. Cases were matched on factors including age, gender, diabetes, tobacco use, blood pressure and body mass index. All subjects had no history of using cholesterol-lowering drugs.

Researchers reviewed data at four points in time prior to cancer diagnosis and found that LDL cholesterol values were lower in cancer subjects than matched controls at each point of assessment throughout an average of 18.7 years prior to diagnosis (p = .038). The trend for lower LDL-C in cancer patients compared with those who were cancer-free was consistent throughout the duration of the study (p = .968 for differences between time points). These findings did not change when controlling for high-density lipoprotein (HDL) cholesterol levels.

Dr. Lavigne cautions the current study does not suggest that having low LDL-C somehow leads to the development of cancer. He recommended that patients diagnosed with high LDL-C should adhere to cholesterol-lowering guidelines, including the use of medications, 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-C, 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," Dr. Lavigne said.