Prostate Cancer Risk Factors
Age
The greatest risk factor for prostate cancer is age. This risk increases significantly after the age of 50 in white men who have no family history of the disease and after the age of 40 in black men and men who have a close relative with prostate cancer. About two-thirds of all prostate cancers are diagnosed in men age 65 and older.
The older you are, the more likely you are to be diagnosed with prostate cancer. Although only 1 in 10,000 men under age 40 will be diagnosed, the rate shoots up to 1 in 38 for ages 40 to 59, and 1 in 15 for ages 60 to 69.
Diet
Research also suggests high dietary fat may be a contributing factor for prostate cancer. The disease is much more common in countries where meat and dairy products are dietary staples compared to countries where the basic diet consists of rice, soybean products, and vegetables.
Some studies have suggested that men who consume a lot of calcium (through food or supplements) may have a higher risk of developing prostate cancer. Dairy foods (which are often high in calcium) might also increase risk. 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 health benefits.
Family history
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 who have a brother with the disease 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 was found.
Studies have identified several inherited genes that appear to increase prostate cancer risk. Testing for these genes is not yet available. Experts estimate that the hereditary form of prostate cancer accounts for just 5% to 10% of all cases.
Genes
Scientists have found several inherited gene changes 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 gene changes is not yet available.
Some inherited gene changes 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 cancer 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.
Recently, some common gene variations have been linked to a higher risk of prostate cancer. Studies to confirm this are needed to see if testing for the gene variants will be useful in predicting prostate cancer risk.
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. The link between the two is not yet clear, but this is an active area of research.
Nationality
For men in the U.S., the risk of developing prostate cancer is 17%. For men who live in rural China, it’s 2%. However, when Chinese men move to the western culture, their risk increases substantially.
Men who live in cities north of 40 degrees latitude (north of Philadelphia, PA, Columbus, OH, and Provo, UT, for instance) have the highest risk for dying from prostate cancer of any men in the United States. This effect appears to be mediated by inadequate sunlight during three months of the year, which reduces vitamin D levels.
Obesity
A measure of obesity, is not linked to being diagnosed with prostate cancer overall. In fact, obese men may have a relatively lower PSA levels than non-obese men due to dilution of the PSA in a larger blood volume. However, obese men are more likely to have aggressive disease.
Most studies have not found that being obese (very overweight) is linked with a higher risk of getting prostate cancer overall.
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.
Some 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 not all studies have found this.
Race/ethnicity
Prostate cancer occurs about 60% more often in African American men than in white American men and when diagnosed is more likely to be advanced. However, Japanese and African males living in their native countries have a low incidence of prostate cancer. Rates for these groups increase sharply when they immigrate to the U.S. African Americans are the second group of men for whom prostate cancer testing should begin at age 40.
Some experts theorize that this suggests an environmental connection, possibly related to high-fat diets, less exposure to the sun, exposure to heavy metals such as cadmium, infectious agents, or smoking. To date, the reasons for these racial differences are not understood.
Sexually transmitted infections
Researchers have 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.
Smoking
Most studies have not found a link between smoking and the risk of developing prostate cancer. Some recent research has linked smoking to a possible small increase in the risk of death from prostate cancer, but this is a new finding that will need to be confirmed by other studies.
Vasectomy
Some earlier studies had suggested that men who have 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.
Risk and Other Prostate Conditions
The most common risk misperception is that the presence of non-cancerous conditions of the prostate will increase the risk of prostate cancer.
While these conditions can cause symptoms similar to those of prostate cancer and should be evaluated by a physician, there is no evidence to suggest that having either of the following conditions will increase a man’s risk for developing prostate cancer.
Prostatitis, an infection in the prostate, is the most common cause of urinary tract infections in men. Most treatment strategies are designed to relieve the symptoms of prostatitis, which include fever, chills, burning during urination, or difficulty urinating. There have been links between inflammation of the prostate cancer and prostate cancer in several studies. This may be a result of being screened for cancer just by having prostate related symptoms, and currently this is an area of controversy.
Benign Prostatic Hyperplasia (BPH) is a non-cancerous enlargement of the prostate. Because the urethra (the tube that carries urine from the bladder out of the body) runs directly through the prostate, enlargement of the prostate in BPH squeezes the urethra, making it difficult and often painful for men to urinate. Learn more about BPH.
More Myths and Non-Risks
Medications - Several recent studies have shown a link between aspirin intake and a reduced risk of prostate cancer by 10-15%. This may result from different screening practices, through a reduction of inflammation, or other unknown factors.
Alcohol - There is no link between alcohol and prostate cancer risk.
Vitamin E - Recent studies have not shown a benefit to the consumption of vitamin E or selenium (in the formulations studied) in the prevention of prostate cancer.
