Age

• Men below the age of 40 are rarely diagnosed with prostate cancer, according to the American Cancer Society (ACS). Risk increases markedly after the age of 50, and roughly 67 percent of all prostate cancer is diagnosed in men who are 65 or older.
  
  

Family History

• The risk is greater in men who have a history of this cancer in their families, suggesting strongly---but not confirming---that there is a genetic or hereditary factor at work. An article in the October 2003 issue of Harvard Men's Health Watch points out that the risk of developing this disease is sharply increased in men whose brothers or fathers have had it.
  
  

African Americans

• The incidence of prostate cancer is higher among African-American men than among men of any other race in the United States, according to ZERO: The Project to End Prostate Cancer. African Americans have the highest rate of prostate cancer in the world, according to ZERO. Prostate cancer rates are higher for non-Hispanic whites than for either Asian Americans or Hispanics.
  
  

Diet

• Men who eat a diet rich in high-fat dairy products and red meat face an increased risk of prostate cancer, according to the ACS. Although there is no conclusive evidence, the ACS says that higher-than-normal calcium consumption may also increase the risk of developing this cancer.
  
  

History of Prostatitis

• The ACS reports that men who have been diagnosed with prostatitis (an inflammation of the prostate gland) may be more likely to develop prostate cancer later in life. Some studies suggest such a link and others downplay the relationship, but research continues.
  
  

Nationality

• Prostate cancer seems to be diagnosed much more widely in certain areas of the world than in others, according to the ACS. The incidence of this cancer is greatest among men in North America, the Caribbean basin, Australia and northwestern Europe. The disease is less common in Africa, Asia, Central America and South America. It has been speculated that lifestyle differences may account for these regional disparities, but there is not yet any scientific evidence to back that up. It has also been argued that screening is much more widespread in the regions that report higher prostate cancer rates. This suggests that other areas of the world may have more cases of the cancer that are simply going undetected.