In a season of ritual overeating, Johns Hopkins researchers have come up with another reason for men to watch their diets: Low cholesterol might protect them from the most aggressive form of prostate cancer.
This isn't the first time medical researchers have linked fats to cancer and its consequences. Recent studies have linked obesity to higher death rates from several types of cancer, and a previous Hopkins study found that men on cholesterol-lowering drugs were less likely to develop fast-growing prostate tumors.
Now, researchers led by epidemiologist Elizabeth Platz report that men in a study with low cholesterol were one-third less likely to get high-grade prostate cancer - the type that tends to grow quickly and spread.
"We already know that maintaining a good range of cholesterol concentrations is important for cardiovascular health," said Platz of the Johns Hopkins Bloomberg School of Public Health and the Hopkins Kimmel Cancer Center.
"Now, we know there may be a benefit for other diseases, possibly prostate cancer."
The research was part of a continuing Harvard University study of 18,000 health professionals. That study investigates possible links between nutrition and chronic disease.
In 1993, researchers asked the men to submit blood specimens through the mail. More than 18,000 did so, and their specimens were put in cold storage. Later, the researchers identified 700 men who developed prostate cancer and compared their blood with that of 700 men without evidence of the disease.
The scientists found no difference in the cholesterol levels of men with and without prostate cancer. But they did discover that men with low cholesterol were less likely to get aggressive cancers.
"What we're thinking is that cholesterol doesn't seem to influence the initial development of the disease," Platz said. "Maybe it affects the progression of the disease and the differentiation status" - alterations in the prostate cells when they become aggressively cancerous.
Viewed under a microscope, the cells of high-grade prostate tumors tend to clump together and lose their distinct, orderly appearance. For patients, these cells are more likely to break out of the prostate gland and spread to other tissues, where they can prove fatal.
Men with high-grade prostate cancer are also more likely to have a recurrence after having their prostates surgically removed.
