Every man over the age of 45 is at risk for prostate cancer. Although prostate cancer can occasionally strike younger men, the risk of getting prostate cancer increases with age and more than 70% of men diagnosed with prostate cancer are over the age of 65. Prostate cancer is the most common cancer that men get in the United States behind skin cancer. It is estimated that there will be 189,000 new cases of prostate cancer and 30,200 deaths from prostate cancer in the year 2002 in the United States.

Age
The risk of developing Prostate cancer begins to increase at age 50 years in white men who have no family history of the disease and at age 40 years in African American men or men of any age who have a first-degree relative (father, brother) with prostate cancer.

Race
African American men have an incidence of prostate cancer that is 1.5 times that of whites. The Japanese and mainland Chinese populations have the lowest rates of prostate cancer. Interestingly, although Japanese immigrants to the United States have a higher incidence of prostate cancer than Japanese living in Japan, their rate is still about half that of US whites. Socioeconomic status appears to be unrelated to risk of prostate cancer, and the explanation for racial variability is unknown.

Geography
The incidence of prostate cancer is highest in Scandinavian countries (22 cases per 100,000 population) and lowest in Asia (5 per 100,000). Risk may be inversely related to ultraviolet light exposure, as the incidence increases the farther on lives from the equator.

Family History
Men who have a first-degree relative with prostate cancer have approximately a two-fold increased risk of developing prostate cancer during their lifetime. An individual who has two first-degree relatives with prostate cancer has five-times the chance of developing prostate cancer in their lifetime then do men with no family history of prostate cancer. True hereditary prostate cancer occurs in a very small number of men and tends to develop at a very early age (under 55 years old).

Dietary Fat
Studies have suggested that dietary fat may increase the risk of prostate cancer. However, no definitive proof of its role has yet been found.

Vasectomy
Several large epidemiologic studies suggest that vasectomy may increase the relative risk of prostate cancer by as much as 1.85. However, these same studies do not report an increased risk of dying from prostate cancer associated with vasectomy but do indicate a statistically increased risk of dying from lung cancer. These findings argue against an association between vasectomy and prostate cancer. Currently, this association is unproven and does not constitute grounds for fundamental changes in the use of vasectomy.

Sexual Activity
There is no association between sexual activity in a man or sexually transmitted diseases and the incidence of prostate cancer.

Although there are several known risk factors for getting prostate cancer, no one knows exactly why one man gets it and another doesn't. Some of the most important risk factors for prostate cancer include age, ethnicity, genetics and diet. Age is generally considered the most important risk factor for prostate cancer. The incidence of prostate cancer rises quickly after the age of 60, and the majority of men will have some form of prostate cancer after the age of 80. One of the sayings about prostate cancer is that older men (over the age of 80) die with prostate cancer not from prostate cancer. This saying means that many older men have microscopic disease that doesn't shorten their life expectancy because the cancer takes a long time to grow and become clinically important. However, this saying is only a generalization; sometimes prostate cancer can grow quickly even in older patients.

Another important risk factor for prostate cancer is ethnicity. No one knows exactly why, but prostate cancer is more common in African-American and Latino men than Caucasian men. African-American men have a 1.6 fold higher chance of getting and dying from prostate cancer than Caucasian men. Asian and Native American men have the lowest chances of getting prostate cancer. Some doctors believe that genetic differences are important in explaining the different rates of prostate cancer between different ethnic groups; however, there is some evidence that differences in diets may be the cause. When Asian men move to Western countries like the United States, their chances of getting prostate cancer rise. Men who live in the United States and Northern Europe have the highest rates of prostate cancer, while men who live in South America, Central America, Africa, and Asia all have much lower chances of developing prostate cancer.

There is some evidence that a man's diet may affect his risk of developing prostate cancer. The most common dietary culprit implicated in raising prostate cancer risk is a high fat diet, particularly a diet high in animal fats. Also, a few studies have suggested that a diet low in vegetables causes an increased risk of prostate cancer. There are a few foods that have been implicated in decreasing prostate cancer risk: a diet high in tomatoes (lycopene) has been suggested as well as diet high in omega-3-fatty acids (oils found in fish like salmon and mackerel). Doctors and scientists aren't in full agreement as to the usefulness of eating these foods when in comes to decreasing prostate cancer risk. Diets high in selenium, vitamin D, and soy have all been suggested to decrease prostate cancer risk; but a these are currently under study and data from large trials is needed before firm recommendations can be given about their use for this purpose.

A family history of prostate cancer increases a man's chances of developing the disease. This increase shows itself when a man has either a father or brothers (or both) with prostate cancer, and is even greater when his relatives develop prostate cancer at a young age. A variety of different genetic factors are currently being researched. Variations and mutations in certain genes may be responsible for some increases in prostate cancer rates in families. Men who carry mutations in genes known as BRCA1 or BRCA2 (these are genes implicated in breast and ovarian cancer in women) may have a 2 to 5 fold increase in prostate cancer risk. Men with high levels of testosterone or a hormone known as IGF-1 (insulin-like growth factor 1) seem to be at a higher risk for developing prostate cancer as well.