A risk factor is anything that increases a person's chance of developing a disease, including cancer. Some risk factors can be controlled, such as smoking, and some cannot be controlled, such as age and family history. Although risk factors can influence the development of cancer, most do not directly cause cancer. Some people with several risk factors never develop cancer, while others with no known risk factors do. However, knowing your risk factors and communicating them to your doctor may help you make more informed lifestyle and health-care choices.

Since the exact cause of prostate cancer is still unknown, it is also unknown how to prevent prostate cancer. The following factors can raise a person's risk of developing prostate cancer:

Age. The risk of prostate cancer increases with age, rising rapidly after age 50. More than 80% of prostate cancers are diagnosed in men who are 65 or older.

Race/ethnicity. Black men are at higher risk for prostate cancer than white men. They are more likely to develop prostate cancer at an earlier age and to have aggressive, fast-growing tumors. The precise reasons for these differences are not known, and probably involve both biologic and socioeconomic factors. Prostate cancer occurs most often in North America and northern Europe and is less common in Asia, Africa, and Latin America. Of importance, it appears that its frequency is increasing in Asian populations living in urbanized environments, such as Hong Kong, Singapore, and North American/European cities.

Family history. A man who has a father or brother with prostate cancer has a higher risk of developing the disease than a man who does not. Researchers have discovered specific genes that may possibly be associated with prostate cancer, although these have not yet been shown to cause prostate cancer or to be specific to this disease.

Diet
No study has shown conclusively that diet can directly influence the development of prostate cancer, but many studies have indicated there may be a link. There is not enough information yet to make clear recommendations about the role diet plays in prostate cancer, but the following may be helpful:

• A diet high in fat, especially animal fat, may increase prostate cancer risk. In fact, many doctors believe that a low-fat diet may help to reduce the risk of prostate cancer.
  
   
• A diet high in vegetables, fruits, and legumes (beans and peas) may decrease risk of prostate cancer. It is unclear which nutrients are directly responsible. Lycopene, found in tomatoes and other vegetables, may slow or prevent cancer growth. A low-fat diet that is high in vegetables and fruits can lower blood pressure and the risk of heart disease, with no evidence that such a diet causes harm.
  
   
• Selenium, an element that people get in very small amounts from food and water, may play a role in lowering the risk of prostate and other cancers. Selenium is currently being tested in clinical trials and has not yet been proven to affect prostate cancer risk.
  
   
• It has been suggested that vitamin E may help to reduce the risk of prostate cancer; this is currently being tested in clinical trials and has not yet been proven to alter risk. In some studies of vitamin E in other settings, it has been suggested that there may be inherent cardiovascular risks (for example, an increased chance of having heart-related or blood vessel problems) with the use of high doses of vitamin E, and final judgment on the use of this supplement will require the completion of ongoing clinical trials.

Hormones. High levels of testosterone (a male sex hormone) may speed up or cause the development of prostate cancer. Prostate cancer does not develop in men who, for other reasons, were castrated (the removal of the testicles) before puberty and whose bodies no longer make testosterone. Stopping the body's production of testosterone, called androgen deprivation therapy, or castration, often treats advanced prostate cancer.