Prostate cancer linked to high cholesterol and to gallstones

April 12, 2006. Researchers from Italy have found what they believe to be the first direct link between high cholesterol levels and prostate cancer.

A possible association has been suggested before but evidence has been limited. This new study, published on-line (Wednesday 12 April) in Annals of Oncology, shows a statistically significant direct relationship between the two conditions.

Lead author Dr Francesca Bravi, an epidemiologist from the Istituto di Ricerche Farmacologiche Mario Negri in Milan, said: "Although the study relied on participants' self-reported medical conditions, the absence of an association between prostate cancer and about 10 other medical conditions we investigated indicates that the relationship we found between prostate cancer and high cholesterol appears to be a real one."

The research team worked on data from a case-control study carried out in four Italian areas between 1991 and 2002, involving 1,294 men under age 75 with prostate cancer and 1,451 matched controls admitted to the same hospitals with acute non-cancerous conditions.

All cases and controls were interviewed in hospital by trained interviewers using wide-ranging structured questionnaires. These included a problem-oriented section on patients' medical history covering about 10 non-cancerous conditions, including hypercholesterolaemia (high cholesterol) and gallstones.

In this study high cholesterol was classified as any cholesterol over the normal level (>200 mg/dl or approximately 5 mmol/l).

Dr Bravi said: "We found that, after allowing for any potential confounding factors, men with prostate cancer were around 50% more likely to have had high cholesterol levels than our non-prostate cancer controls. The association was somewhat stronger for men whose high cholesterol levels had been diagnosed before they were 50 and for men over 65, where there was an 80% greater likelihood of high cholesterol levels.

"We also found that prostate cancer patients were 26% more likely to have suffered from gallstones than our controls, with an apparently higher relationship in thinner men. Although that figure was not statistically significant, gallstones are often related to high cholesterol levels. To our knowledge there have been no previous studies reporting any relationship between gallstones and prostate cancer."

Co-author Dr Cristina Bosetti, a senior epidemiologist and biostatistician at the same institute, explained: "Androgens - hormones that have a role in prostate tissue and cancer - are synthesised from cholesterol, suggesting a possible biological relationship between high cholesterol and prostate cancer. Gallstones are related to high cholesterol levels as well and are often composed of cholesterol. So, the direct relationship we found between gallstones and prostate cancer, while it was not statistically significant, suggests a similar biological mechanism may explain the link."

This study had relied on participant's self-reporting medical conditions: the researchers believe that their results should be confirmed by further studies, including prospective investigations with reliable measured cholesterol levels.

Dr Bosetti concluded: "There are some laboratory data suggesting statins may have preventive potential against prostate cancer and our results do give an indirect suggestion that statins may help in lowering prostate cancer risk. However, studies to date on cholesterol-lowering statins and prostate cancer have been limited and inconclusive."