Men with high cholesterol levels have a 50 per cent higher risk of prostate cancer, says Italian research.
High cholesterol levels, hypercholesterolaemia, have a long association with many diseases, particularly cardiovascular disease. The link with prostate cancer is backed up by only limited evidence.
Over half a million men worldwide are diagnosed with prostate cancer every year, with over 200,000 deaths from the disease. The lowest incidence of the cancer is in Asia and the Far East, in particular India, Japan and China.
The new study, published on-line in the Annals of Oncology (doi: 10.1093/annonc/mdl080), reported: "The present study found a direct association between hypercholesterolaemia and prostate cancer, which has been only sporadically reported previously."
The case-control study, led by Francesca Bravi from the Istituto di Ricerche Farmacologiche Mario Negri in Milan, investigated cholesterol levels of 1294 men with clinically diagnosed prostate cancer, and 1451 controls with no prostate cancer.
Medical histories were obtained by self-reporting methods, not verified by using medical records, using a questionnaire. Despite the cases and controls being interviewed in hospital by trained interviewers, the self-reporting is a weakness in the study.
Results were adjusted to allow for possible confounding factors, such as body mass index, smoking habits, alcohol consumption, and family history of the disease.
After taking into account these possible complicating factors, the researchers found that hypercholesterolaemia was associated with a 50 per cent increase in the risk of prostate cancer.
The risk is even higher for hypercholesterolaemic men over 65, who increase their risk of the cancer by 80 per cent, whereas younger men had a 32 per cent increased risk.
The researchers suggest that the increased risk is linked to higher levels of prostate specific antigen (PSA), a protein that is used as a marker for the disease, in men with high cholesterol levels. Raised levels of PSA are indicative of prostate cancer risk, although two-thirds of men with high PSA levels will not have prostate cancer.
Some experts argue against the cholesterol-PSA link, saying that the metabolic products of cholesterol are carcinogenic and that this may be the mechanism responsible.
Chris Hiley, head of policy for the UK's Prostate Cancer Charity said that the study was very interesting, and may help explain why Western, developed countries with had such high incidences of the disease.
"It also suggests that if men make lifestyle changes and adopt a healthy, low cholesterol diet it might reduce their risk of prostate cancer.
"Further research is needed to confirm this, but in the meantime the health benefits of a varied diet are indisputable. We encourage men to cut down their intake of fatty foods and red and processed meat, but continue to eat oily fish and a high fibre diet with porridge oats, as well as plenty of fresh fruit and vegetables daily," she added.
Food industry executives polled by Reuters Business Insight last year predicted that by 2009, cholesterol-lowering foods would be the most profitable health food, far ahead of recently trendy products such as low-carb foods.