Low cholesterol associated with cancer in diabetics

August 25, 2008

Low levels of LDL cholesterol as well as high levels are associated with cancer in patients with type 2 diabetes, found a prospective cohort study published in CMAJ.

Researchers from the Hong Kong Institute of Diabetes and Obesity, the Li Ka Shing Institute of Health Sciences and The Chinese University of Hong Kong conducted a study of 6107 Chinese patients with type 2 diabetes and found a V-shaped risk relation between LDL cholesterol and cancer in patients not receiving statin therapy.

"LDL cholesterol levels below 2.80 mmol/L and levels of at least 3.90 mmol/L were both associated with markedly elevated risk of cancer among patients who did not use statins," state Dr. Juliana Chan and coauthors.

The study excluded people on statins as statins obscured the association between LDL cholesterol and all-site cancer.

Increasing data suggests an association between type 2 diabetes and an elevated risk of cancer, including breast, colorectal, pancreatic and liver cancers. An elevated risk of cancer in patients with low LDL was linked to cancers of digestive organs and peritoneum, genital and urinary organs, lymphatic and blood tissues as well as other areas. Patients with an LDL cholesterol level above 3.80 mmol/L had heightened risks of oral, digestive, bone, skin, connective tissue, breast and other cancers.

Regarding clinical implications, the authors suggest "the use of these levels as risk markers may help clinicians to assess their patients more fully and thus to prevent premature deaths in patients who have high risk."

They call for re-analysis of data from clinical trials to confirm or refute these findings.

In a related commentary, Drs. Frank Hu and Eric Ding of Harvard School of Public Health say confounding factors such as indication for the use of statins, lifestyle and socioeconomic status must be considered when looking at the association of high levels of LDL cholesterol and the risk of cancer.

"Low serum cholesterol is commonly observed in individuals with ill health (e.g. cancer patients) and those with unhealthy lifestyle characteristics such as smoking and heavy drinking," states Hu.

Link: http://www.cmaj.ca/press/pg427.pdf

Source: Canadian Medical Association Journal