TUESDAY, April 11, 2006 (HealthDay News) -- Italian researchers have found what they call the first direct association between high cholesterol levels and prostate cancer.
In a nine-year study of almost 3,000 men, the researchers discovered that those with prostate cancer, particularly older men, were twice as likely to have high cholesterol as those without.
U.S. experts, however, pointed out the possibility that the two conditions are only indirectly connected through a third factor.
"This is an interesting observation, but prostate cancer is linked with obesity and diabetes -- both of which are known risk factors for high cholesterol," noted Dr. Jay Brooks, chairman of hematology/oncology at the Ochsner Health System in Baton Rouge, La. "I would say that's the correlation."
"It says nothing definitive, but it raises an interesting question," added Dr. Ronald Ennis, director of radiation oncology at St. Luke's Roosevelt Hospital and associate director of Continuum Cancer Centers, both in New York City. "Whether the findings are a fluke of the patient population or if there's a real relationship is very uncertain right now."
The findings were published Wednesday in the online edition of the Annals of Oncology.
While age, ethnicity and family history help determine who will get prostate cancer, other causes are poorly understood, the study authors from the Istituto di Ricerche Farmacologiche Mario Negri in Milan, explained.
Diabetes, cardiovascular conditions and obesity have been associated with prostate cancer but the evidence has not been consistent, they added. High cholesterol has been listed as a culprit but, again, the evidence has been sketchy.
For this study, the researchers looked at almost 1,300 men under the age of 75 who had prostate cancer and compared them with 1,451 men who did not have the illness, but had been admitted to the same hospitals with acute, non-cancerous conditions. The study took place between 1991 and 2002.
Participants answered questions about their medical conditions and medical history. The presence of prostate cancer was confirmed by lab tests. The existence of high cholesterol came from the participants' say-so, which could be considered a study weakness.
Men with prostate cancer were 50 percent more likely to have high cholesterol than men without prostate cancer, the Italian team found. The association was stronger in those over 65 (who were 80 percent more likely to also have high cholesterol) than in younger men (who were only 32 percent more likely to have high cholesterol).
The prostate cancer patients in the study were also 26 percent more likely to have had gallstones than the controls, but this was not considered to be statistically significant. According to the authors, gallstones are often related to high cholesterol levels.
The association between high cholesterol levels and prostate cancer was also stronger in men diagnosed with high cholesterol before the age of 50.
As for the biological plausibility, the study authors point to the fact that androgens or male hormones that play a role in cancer and in prostate tissue are synthesized from cholesterol.
If future studies bear out these results, statins (popular cholesterol-lowering drugs like Lipitor or Pravachol) may have a role in preventing prostate cancer, the authors said.
So far, the evidence regarding statins and prostate cancer has been inconclusive, however.
"If they could look at databases of people who have high cholesterol or follow people long-term, that would be interesting," Ennis said.
According to the American Cancer Society, prostate cancer is the most common type of cancer in American men after skin cancer. An estimated 234,460 new cases of prostate cancer will be diagnosed in the U.S. in 2006 and about 27,350 men will die of the disease. Prostate cancer is the second leading cause of cancer death in men, following lung cancer.
For more on prostate cancer, head to the American Cancer Society.