Risk Factors for Prostate
A risk factor is anything that affects your
chance of getting a disease such as cancer. Different cancers have
different risk factors. For example, exposing skin to strong
sunlight is a risk factor for skin cancer. Smoking is a risk
factor for many cancers.
But risk factors don't tell us everything. Many people with one or
more risk factors never get cancer, while others with this disease
may have had no known risk factors.
Although we don't yet completely understand the causes of prostate
cancer, researchers have found several factors that may change the
risk of getting it. For some of these factors, the link to
prostate cancer risk is not clear, yet.
Age is the strongest risk factor for prostate cancer. Prostate
cancer is very rare before the age of 40, but the chance of having
prostate cancer rises rapidly after age 50. Almost 2 out of 3
prostate cancers are found in men over the age of 65.
Prostate cancer occurs more often in African-American men than in
men of other races. African-American men are also more likely to
be diagnosed at an advanced stage, and are more than twice as
likely to die of prostate cancer as white men. Prostate cancer
occurs less often in Asian-American and Hispanic/Latino men than
in non-Hispanic whites. The reasons for these racial and ethnic
differences are not clear.
Prostate cancer is most common in North America, northwestern
Europe, Australia, and on Caribbean islands. It is less common in
Asia, Africa, Central America, and South America. The reasons for
this are not clear. More intensive screening in some developed
countries likely accounts for at least part of this difference,
but other factors are likely to be important as well. For example,
lifestyle differences (diet, etc.) may be important: men of Asian
descent living in the United States have a lower risk of prostate
cancer than white Americans, but their risk is higher than that of
men of similar backgrounds living in Asia.
Prostate cancer seems to run in some families, which suggests that
in some cases there may be an inherited or genetic factor. Having
a father or brother with prostate cancer more than doubles a man's
risk of developing this disease. (The risk is higher for men with
an affected brother than for those with an affected father.) The
risk is much higher for men with several affected relatives,
particularly if their relatives were young at the time the cancer
Scientists have found several inherited genes that seem to raise
prostate cancer risk, but they probably account for only a small
number of cases overall. Genetic testing for most of these genes
is not yet available. Recently, some common gene variations have
been linked to the risk of prostate cancer. Studies to confirm
these results are needed to see if testing for the gene variants
will be useful in predicting prostate cancer risk.
Some inherited genes raise the risk for more than one type of
cancer. For example, inherited mutations of the BRCA1 or BRCA2
genes are the reason that breast and ovarian cancers are much more
common in some families. Mutations in these genes may also
increase prostate cancer risk in some men, but they account for a
very small percentage of prostate cancer cases.
The exact role of diet in prostate cancer is not clear, although
several different factors have been studied.
Men who eat a lot of red meat or high-fat dairy products appear to
have a slightly higher chance of getting prostate cancer. These
men also tend to eat fewer fruits and vegetables. Doctors are not
sure which of these factors is responsible for raising the risk.
Some studies have suggested that men who consume a lot of calcium
(through food or supplements) may have a higher risk of developing
advanced prostate cancer. Most studies have not found such a link
with the levels of calcium found in the average diet, and it's
important to note that calcium is known to have other important
Most studies have not found that being obese (having a high amount
of extra body fat) is linked with a higher risk of getting
prostate cancer. Some studies have found that obese men have a
lower risk of getting a low-grade (less dangerous) form of the
disease, but a higher risk of getting more aggressive prostate
cancer. The reasons for this are not clear. Studies have also
found that obese men may be at greater risk for having more
advanced prostate cancer and of dying from prostate cancer, but
this was not seen in other studies.
Exercise has not been shown to reduce prostate cancer risk in most
studies. But some studies have found that high levels of physical
activity, particularly in older men, may lower the risk of
advanced prostate cancer. More research in this area is needed.
Inflammation of the prostate
Some studies have suggested that prostatitis (inflammation of the
prostate gland) may be linked to an increased risk of prostate
cancer, but other studies have not found such a link. Inflammation
is often seen in samples of prostate tissue that also contain
cancer. While the link between the two is not yet clear, this is
an active area of research.
Researchers have also looked to see if sexually transmitted
infections (like gonorrhea or chlamydia) might increase the risk
of prostate cancer, possibly by leading to inflammation of the
prostate. So far, studies have not agreed, and no firm conclusions
have been reached.
Some earlier studies had suggested that men who had a vasectomy
(minor surgery to make men infertile) -- especially those younger
than 35 at the time of the procedure -- may have a slightly
increased risk for prostate cancer. But most recent studies have
not found any increased risk among men who have had this
operation. Fear of an increased risk of prostate cancer should not
be a reason to avoid a vasectomy.