The exact answer to this question is still unknown. What we do know is that there is a large variation in the incidence of the disease worldwide and that there exists a significant difference amongst various ethnic groups. These variations suggest the following as possibilities as causative mechanisms in the development of prostate cancer:
The disease is very uncommon in men under the age of 50 years. It becomes more common with age thereafter. Data from autopsy studies shows that up to 80% of men aged 80 years have evidence of the disease.
2. Family history
The risk of the disease increases with the number of affected first degree relatives up to an almost 100% risk if there are 3 or more individuals within a family.
3. Ethnic origin
The lowest incidence in the world is amongst Asian men, however, after migration to countries where the incidence is higher, their incidence also increases. African American men have the highest incidence in the world and the highest age-specific mortality rate, suggesting that this ethnic group is prone to a more aggressive form of the disease.
This is an area that is currently being extensively researched at the moment. There appears to be an increased risk with high intake of animal fat. It is also thought that high intake of soy products may be protective. Both selenium and vitamin E are thought to have a protective effect as are lycopenes which are responsible for the red colour in tomatoes. I general terms, a balanced healthy diet containing several daily portions of fruit and vegetables with limited intake of red meat is the most suitable.
5. Male sex hormones
Some studies suggest that higher levels or changes in receptors may increase a man’s risk of the disease.