The causes of prostate cancer are not well understood. Doctors cannot explain why one man gets prostate cancer and another does not.
Studies have found that the following risk factors are associated with prostate cancer:
- Age. In the United States, prostate cancer is found mainly in men over age 55. The average age of patients at the time of diagnosis is 70.
- Family history of prostate cancer. A man's risk for developing prostate cancer is higher if his father or brother has had the disease.
- Race. This disease is more common in African American men than in white men. It is less common in Asian and American Indian men.
- Diet and dietary factors. Some evidence suggests that a diet high in animal fat may increase the risk of prostate cancer and a diet high in fruits and vegetables may decrease the risk. Studies are in progress to learn whether men can reduce their risk of prostate cancer by taking certain dietary supplements.
Although a few studies suggested that having a vasectomy might increase a man's risk for prostate cancer, most studies do not support this finding. Scientists have studied whether benign prostatic hyperplasia, obesity, lack of exercise, smoking, radiation exposure, or a sexually transmitted virus might increase the risk for prostate cancer. At this time, there is little evidence that these factors contribute to an increased risk.