Causes of prostate cancer

Causes
The specific causes of prostate cancer remain unknown.[8] A man's risk of developing prostate cancer is related to his age, genetics, race, diet, lifestyle, medications, and other factors. The primary risk factor is age. Prostate cancer is uncommon in men younger than 45, but becomes more common with advancing age. The average age at the time of diagnosis is 70.[9] However, many men never know they have prostate cancer. Autopsy studies of Chinese, German, Israeli, Jamaican, Swedish, and Ugandan men who died of other causes have found prostate cancer in thirty percent of men in their 50s, and in eighty percent of men in their 70s.[10] In the year 2005 in the United States, there were an estimated 230,000 new cases of prostate cancer and 30,000 deaths due to prostate cancer.[11]

[edit] Genetics
A man's genetic background contributes to his risk of developing prostate cancer. This is suggested by an increased incidence of prostate cancer found in certain racial groups, in identical twins of men with prostate cancer, and in men with certain genes. In the United States, prostate cancer more commonly affects black men than white or Hispanic men, and is also more deadly in black men.[12] Men who have a brother or father with prostate cancer have twice the usual risk of developing prostate cancer.[13] Studies of twins in Scandinavia suggest that forty percent of prostate cancer risk can be explained by inherited factors.[14] However, no single gene is responsible for prostate cancer; many different genes have been implicated. Two genes (BRCA1 and BRCA2) that are important risk factors for ovarian cancer and breast cancer in women have also been implicated in prostate cancer.[15]

[edit] Diet
Dietary amounts of certain foods, vitamins, and minerals can contribute to prostate cancer risk. Dietary factors that may increase prostate cancer risk include the mineral selenium[citation needed]. A study in 2007 cast doubt on the effectiveness of lycopene (found in tomatoes) in reducing the risk of prostate cancer.[16] Lower blood levels of vitamin D also may increase the risk of developing prostate cancer. This may be linked to lower exposure to ultraviolet (UV) light, since UV light exposure can increase vitamin D in the body.[17]
A large study has implicated dairy, specifically low-fat milk and other dairy products to which vitamin A palmitate has been added. This form of synthetic vitamin A has been linked to prostate cancer because it reacts with zinc and protein to form an unabsorbable complex.[citation needed]

[edit] Medication exposure
There are also some links between prostate cancer and medications, medical procedures, and medical conditions. Daily use of anti-inflammatory medicines such as aspirin, ibuprofen, or naproxen may decrease prostate cancer risk.[18] Use of the cholesterol-lowering drugs known as the statins may also decrease prostate cancer risk.[19] Infection or inflammation of the prostate (prostatitis) may increase the chance for prostate cancer. In particular, infection with the sexually transmitted infections chlamydia, gonorrhea, or syphilis seems to increase risk.[20] Finally, obesity[21] and elevated blood levels of testosterone[22] may increase the risk for prostate cancer.
Research released in May 2007, found that US war veterans who had been exposed to Agent Orange had a 48% increased risk of prostate cancer recurrence following surgery.[23]