Cholesterol en prostaatkanker.*
Uit een studie blijkt dat mannen met lagere cholesterolwaarden wel 40 tot 50% minder kans hebben op het ontwikkelen van een agressieve vorm van prostaatkanker. Uit dit onderzoek lijkt het dat cholesterolwaarden niet maatgevend zijn voor het ontstaan van prostaatkanker doch als prostaatkanker zich openbaart de agressiviteit van de tumor veel groter is bij hogere bloedwaarden cholesterol. Bij welke cholesterolwaarden precies deze verandering plaatsvindt is niet echt duidelijk geworden.
Association
between plasma cholesterol and prostate cancer
Prostate
cancer patients who had lower levels of cholesterol in their blood had a
significantly reduced chance of developing more aggressive forms of the disease,
compared to patients with higher cholesterol readings.
The
researchers looked at cholesterol levels first because cholesterol affects cell
signaling and survival. Some scientists theorize that a large quantity of
cholesterol in the blood could stimulate the survival of abnormal prostate cells.
They
studied blood drawn from 698 men before they were diagnosed with prostate cancer
and matched it to blood taken from 698 men who had not been diagnosed with the
disease. All of the men participated in Harvard University's Health
Professionals Follow-up Study, a group of 18,018 participants who provided a
blood sample between 1993 and 1995.
They
found that mean cholesterol levels did not differ between the men with prostate
cancer and the control participants, suggesting that cholesterol was not
involved in the initial development of prostate cancer, Platz said.
But
when comparing men who had the lowest quartile of serum cholesterol to men who
had the highest, they found that prostate cancer patients with lower cholesterol
had the lowest risk of developing a more worrisome form of the disease. They
specifically found that the risk of being diagnosed with high-grade or advanced
cancer was reduced by 40 percent and 50 percent, respectively.
Platz
says it is not clear at what levels serum cholesterol may stimulate the abnormal
growth seen in cancer development. "The findings suggest either that high
cholesterol may push existing prostate cancer to become aggressive, or,
alternatively, very low levels of cholesterol may provide protection against
development of an aggressive cancer," she said. "We just don't know
which it is at this point."
She
also said that because the findings come from an observational study, not a
trial, it is impossible to conclude that men can lower their risk of developing
an aggressive form of prostate cancer by reducing their intake of saturated fat,
the type of fat that increases serum cholesterol, which some studies have linked
to an increased risk of advanced prostate cancer.
"It is too soon to say that such measures would be specifically beneficial to lowering such a risk, but for good health in general, it is prudent to consume a diet that contains healthful fats that do not increase serum cholesterol," she said. (Nov. 2006)