While the causes of prostate cancer are not completely understood, many factors may contribute to prostate cancer risk. The main risk factors are age, family history and genetics, race, nationality or where you live, and hormones. Other factors, such as diet and obesity, may also contribute to prostate cancer risk.
The biggest risk factor for developing prostate cancer is simply getting older. Although prostate cancer can occur at any age, it is most often found in men over age 50, and more than two-thirds of men diagnosed with the disease are over 65.
Family History and Genetics
Inherited or genetic factors may also be involved. Research indicates that a family history of prostate cancer may increase your risk of developing the disease, particularly if you have a number of close relatives who were younger than 60 when they were diagnosed. If your father or brother had prostate cancer, your risk is two to three times greater than the risk for someone with no family history of the disease. Scientists—including researchers at Fred Hutchinson Cancer Research Center, a Seattle Cancer Care Alliance (SCCA) founding organization—are working to find the genes responsible for this familial risk.
Race or Ethnicity
African-American men are more likely than men of other races to develop prostate cancer. The disease is less common among men of Asian or Hispanic/Latino descent than among those of European descent. The reasons for these racial and ethnic differences are not clear.
Nationality or Where You Live
Prostate cancer is most common in North America, northwestern Europe, Australia, and the Caribbean and is less common in Asia, Africa, and Central and South America. Screening may account for some of this difference; however, lifestyle differences, such as diet, may also be factors.
Research suggests that the development of prostate cancer is linked to higher levels of certain hormones, such as testosterone, the main male sex hormone. Testosterone is changed into dihydrotestosterone (DHT) by an enzyme in the body. DHT is important for normal prostate growth but can also cause the prostate to get bigger and may play a role in development of prostate cancer.
Diet and Obesity
Although the reasons are unclear, scientists believe a critical factor is diet. A diet high in red meat, dairy foods, and calcium and low in fruits and vegetables may play a part in causing prostate cancer. Vitamin E and folic acid are also thought to increase the risk of prostate cancer.
Studies have not shown a clear link between obesity and prostate cancer, but in some studies obese men have had a lower risk of getting a low-grade form of the disease but a higher risk of getting more aggressive prostate cancer. In addition, several studies have found that obese men may be at greater risk of having more advanced prostate cancer and of dying from prostate cancer.
Researchers are studying how nutrition, such as a diet low in fat and high in soy protein and fiber, may reduce the risk of prostate cancer. They are also studying whether men can reduce their risk through exercise and by taking certain dietary supplements. A diet rich in vegetables—especially cruciferous vegetables (broccoli, cabbage, cauliflower, kale, collard, mustard greens, horseradish, Brussels sprouts, radishes, turnips, rutabaga, and kohlrabi)—and folate (a B vitamin found naturally in some foods) is associated with a reduced risk of prostate cancer. Read more about the impact of diet and exercise on prostate cancer.
Other Possible Risk Factors
Scientists have also studied whether having an inflamed or enlarged prostate, having a vasectomy, smoking, being exposed to radiation, or having a sexually transmitted virus might increase prostate cancer risk. At this time, there is little evidence that these factors contribute to risk.