Prostate Screening
What are the risk factors for prostate cancer?
A risk factor is anything that increases a person's chance of getting a disease such as cancer. Different cancers have different risk factors. Although risk factors increase a person's risk, they do not necessarily cause the disease. Many people with one or more risk factors never develop the disease, while others who do get the disease have no apparent risk factors. But it is important to know about risk factors so that you can do everything possible to give yourself the best chance of avoiding the disease.
The causes of prostate cancer are not well understood, but researchers have found several factors that are consistently associated with an increased risk of developing this disease. The role of some other factors is less certain because they have been suggested by some but not all studies to increase the risk of prostate cancer.
Age is the strongest risk factor for prostate cancer. The disease is rare in men under age 45, but incidence rates rise rapidly with age after 50. The annual incidence rates in the U.S. from 1992 to 1996 were 49.6 cases per 100,000 men under age 65, and 1131.9 cases per 100,000 men ages 65 and older. More than 80% of all prostate cancers are diagnosed in men over the age of 65. Autopsy studies also show that the prevalence of latent prostate cancer increases directly with age.
Another major risk factor for which the evidence is strong is family history. Having a father or a brother with prostate cancer doubles a man's risk of developing the disease. The risk is even higher for men with several affected relatives, particularly if their relatives were young at the time of diagnosis. A third major risk factor is race. African American men have significantly higher incidence rates than Caucasian American men, though incidence among Caucasian men is rising faster, probably as a result of intensified screening. Mortality rates among African American men are twice as high as those of Caucasian men. They are also typically diagnosed at a later stage than Caucasian men. Other ethnicities, including Hispanic, Asian, and Native Americans have lower rates than either Caucasians or African Americans.
Diet also seems to play a role as a risk factor, but it is not clear-cut. Fat in the diet has been suggested to increase risk but other research indicates that men who eat a high-fat diet also tend to eat fewer fruits and vegetables and more dairy products and that these may be responsible for some of the increased risk that has been attributed to fat. Recent research has suggested that a diet high in calcium and low in fructose (fruit sugar) increases prostate cancer risk. The most consistent evidence for a dietary factor involves the antioxidant carotenoid, lycopene. Eating an abundance of it, which is found primarily in tomato-based products, has been shown to reduce the risk of prostate cancer.
Other factors that have been suggested to increase risk but for which the evidence is weaker include a prior vasectomy, being overweight, low levels of physical activity, alcohol consumption, and smoking.
