What is a risk factor?
A risk factor is anything that may increase a person's chance of developing a disease. It may be an activity, such as smoking, diet, family history, or many other things. Different diseases, including cancers, have different risk factors.
Although these factors can increase a person's risk, they do not necessarily cause the disease. Some people with one or more risk factors never develop cancer, while others develop cancer and have no known risk factors.
Knowing your risk factors for any disease can help to guide you into the appropriate actions, including changing behaviors and being clinically monitored for the disease.
What are risk factors for prostate cancer?
In general, all men are at risk for prostate cancer. However, there are specific risk factors that increase the likelihood that certain men will develop the disease, including the following:
Race. Prostate cancer is more common among African-American men than it is among Caucasian American men. Japanese and Chinese men native to their country have the lowest rates of prostate cancer. Interestingly, when Chinese and Japanese men immigrate to the U.S., they have an increased risk and mortality rate from prostate cancer, when compared to their native populations. In Japan, the incidence of prostate cancer has increased as Western diets and lifestyles have been adopted.
Environmental exposures. Some studies show an increased chance for prostate cancer in men who are farmers, or those exposed to the metal cadmium while making batteries, welding, or electroplating. Additional research is needed in this area to confirm whether this is a true association.
Having a vasectomy, BPH (benign prostatic hyperplasia), or STD (sexually transmitted disease). Researchers have looked at whether men who have had a vasectomy, BPH, or those who have been exposed to a sexually transmitted disease are at increased risk for prostate cancer. Some studies suggest a link, while others do not support these claims.
Family history of prostate cancer. Having a father or brother with prostate cancer more than doubles or triples a man's risk of developing this disease. The risk is even higher for men with several affected relatives, particularly if the relatives were young at the time of diagnosis. Geneticists (doctors and scientists who study inheritance and the causes of genetic disease) divide families into three groups, depending on the number of men with prostate cancer and their ages of onset, including the following:
Sporadic. A family with prostate cancer present in one man, at a typical age of onset; sporadic means occurs by chance.
Familial. A family with prostate cancer present in more than one person, but with no definitive pattern of inheritance and usually an older age of onset.
Hereditary. A family with a cluster of three or more affected relatives within any nuclear family (parents and their children), a family with prostate cancer in each of three generations on either the mother or father's side, or a cluster of two relatives affected at a young age (55 or less). Five to 10 percent of prostate cancer cases are considered hereditary.
Genetic factors. In the center of each cell of the human body, our genetic material--chromosomes--are found. Normally, cells contain 46 chromosomes, or 23 pairs, half of which are inherited from our mother, half from our father. The chromosomes contain the body's blueprint, our genes. Genes code for traits, such as eye color and blood type, and also control important regulatory functions in the body, such as the rate of cell growth. Some genes, when altered or mutated, give a higher risk for uncontrolled cell growth, which, in turn, can lead to tumor development. These genes have various names, but overall are referred to as cancer susceptibility genes. Approximately 5 to 10 percent of all prostate cancers are known to be attributed to an inherited DNA change, such as a cancer susceptibility gene.