Causes and Risk Factors of Prostate Cancer

Prostate cancer begins when a series of gene mutations in the DNA of a prostate cell cause it to grow and divide in an out-of-control fashion. The exact causes have yet to be determined, but it's thought that most prostate cancers develop due to a combination of factors.

Known risk factors for the disease include age, race, and geographical location. Researchers are also looking into potential connections to environmental exposures to pesticides and herbicides, diet, vitamin D deficiency, and even sexual activity. A family history of prostate cancer and certain genetic mutations are also associated with the development of prostate cancer at a younger age.

Prostate cancer risk factors
Illustration by JR Bee, Verywell

Common Risk Factors

When cancer cells divide and grow, they form a tumor that can eventually invade nearby tissue and sometimes break off and spread (metastasize) to other regions of the body. But again, what causes this in the first place is not concrete.

Risk factors are conditions that are associated with an increased risk of developing prostate cancer but do not necessarily cause prostate cancer.

Men who have more risk factors may wish to be screened more often or at an earlier age than men without these risk factors.

That said, prostate cancer can and does occur in men who do not have any obvious risk factors, and any man is potentially at risk for the disease.

Possible risk factors include:


The risk of prostate cancer increases with age, and roughly 60% of cases are diagnosed after the age of 65. It is uncommon before the age of 40, and when seen in younger men, is often associated with a family history of the disease in male relatives or breast cancer in female relatives.

prostate cancer: newly diagnosed cases
Illustration by Verywell


Black men have a greater risk of prostate cancer than do men of other races and are more likely to develop the disease at a young age. In Black men, prostate cancer is also more likely to be aggressive, though the reason for this is unclear.

American Asian and Hispanic men have a lower risk of prostate cancer than their non-Hispanic white counterparts. Factors other than ethnicity are likely involved, since Asian-American men have a higher incidence of prostate cancer than Asian men living in Asia, and the incidence of prostate cancer in Asian men living in the United States and Europe is currently increasing.


Prostate cancer is more common in some areas of the world, with a higher incidence in North America, Europe, and Australia than other regions. 

Possible Risk Factors

In addition to the known risk factors, there are a number of factors that are being investigated as to their potential role in either increasing or reducing the risk of prostate cancer.


The role of diet in the development of prostate cancer has long been debated. It appears that a diet rich in red meats and dairy products, as well as high in calcium, may be associated with an increased risk (though not all studies have found these associations). Conversely, a diet rich in fruits and vegetables may have a protective effect.

In addition to a possible link with the development of prostate cancer, dairy products have been linked with poorer outcomes in men who already have the disease. Whole milk consumption was found to be associated with an increased risk of prostate cancer recurrence in men who already have the disease, according to a 2017 study.

2015 study found that men who continued to consume a Western diet after a diagnosis of prostate cancer had an increased risk of death.

Environmental Exposures

Some chemicals and occupational exposures have been linked to the development of prostate cancer. These include:

  • Cadmium: The risk related to cadmium exposure appears to be enhanced by a zinc deficiency in the diet.
  • Herbicides: In the past, the possible role of Agent Orange exposure in prostate cancer was controversial, but more recent research reveals a more consistent association between exposure and prostate cancer. Exposed veterans have at least a 50% greater risk of developing prostate cancer, and cancers that occur tend to be more aggressive and more likely to metastasize.
  • Pesticides: Men who apply pesticides or work in the production of pesticides may have an increased risk of prostate cancer. This increased risk, according to a 2015 study, is primarily in men who also have a family history of the disease.
  • Smoke: There are a number of different compounds in smoke exposure that may contribute to this increased risk in firefighters.

There are likely environmental factors that have not yet been identified that play a role in the development of prostate cancer.

Of note, men who have a brother with prostate cancer have a higher risk of the disease than men who have a father with the disease (both fathers and brothers are considered first-degree relatives).

This suggests that the increased risk in a brother versus a father is due to environmental factors.

Vitamin D Deficiency and Sun Exposure

Vitamin D behaves like a hormone in the body and is produced in the skin upon exposure to ultraviolet light from the sun. It's been known for some time that men who live in northern regions are more likely to develop the disease than those in southern latitudes, and this increased risk is thought by some to be related to vitamin D deficiency.

Other research has suggested that high serum vitamin D levels may reduce the risk of aggressive prostate cancer. Fortunately, vitamin D levels can be tested a via a simple blood test, and men can talk to their healthcare providers about supplementation if needed.

Sexual Activity

At one time it was thought that men who were more sexually active (had more ejaculations per month) were more likely to develop prostate cancer. The thought was that these men may be more likely to develop a sexually transmitted disease that could cause inflammation in the prostate and, hence, lead to cancer, or that they had higher testosterone levels (testosterone can "feed" the growth of prostate cancers).

This myth has been dispelled in a few large studies, and according to a 2016 follow-up study, men who have more ejaculations per month (21 in the study) appeared to have a significantly lower risk of developing prostate cancer than those who had fewer (four to seven or less).

With colon cancer, less frequent bowel movements are associated with an increased risk of the disease, presumably because toxins in stool are in contact with the mucosa of the bowel for a longer period of time. The same principle could be at play with prostate cancer, with fewer ejaculations resulting in any carcinogens present having longer contact with the tissues in the prostate.


Chronic prostatitis secondary to sexually transmitted infections has been correlated with an increased risk of prostate cancer in some studies. However, other studies have shown conflicting results, and currently the research is inconclusive.

Other Concerns

You may also hear of other potential risk factors for prostate cancer. It's important to sort the fact from fiction:

  • Vasectomy: The possibility that vasectomy is associated with prostate cancer has been debated for some time, though more recent studies have found no correlation between either vasectomy or vasectomy reversal and the occurrence of prostate cancer.
  • Immunosuppression: Having a compromised immune system has not been linked with an increased risk of prostate cancer, but prostate cancers that do occur may be more aggressive.
  • Obesity: Men who are overweight or obese do not appear to have a greater risk of developing prostate cancer, but an elevated body mass index has been linked with tumors that are more aggressive and more difficult to treat.


Genetics clearly play a role in prostate cancer. Several gene mutations have been linked to the development of prostate cancer, but not all men who have a family history of the disease will have a detectable mutation.

The science looking at gene mutations and their role in cancer is in its infancy, and it's likely that there are a number of gene mutations associated with prostate cancer that have not yet been discovered. It's also possible that it is a combination of genetic factors that raise the risk for some men. Therefore, even if a man does not have a known gene mutation, he should talk to his healthcare provider if he has a relevant family history.

Prostate Cancer Doctor Discussion Guide

Get our printable guide for your next healthcare provider's appointment to help you ask the right questions.

Doctor Discussion Guide Man

Family History

Men who have a father, brother or son who has prostate cancer have a higher risk of developing prostate cancer. The risk is greater if a male relative has had prostate cancer at a young age, or if many men in a family are affected.

It can be difficult to separate out genetics and environmental factors as a cause.

Overall, around 20% of prostate cancers are considered "familial" and that could be due to a combination of shared genes and shared lifestyles.

Men who have a family history of breast cancer in female relatives also have an increased risk of developing the disease.

Gene Mutations and Genetic Syndromes

It's thought that 10% of prostate cancers are related to inherited mutations for which testing is now available. The chance that a prostate cancer is hereditary is increased if at least three relatives have had prostate cancer.

Some genetic changes associated with prostate cancer include:

  • BRCA gene mutations: Both BRCA1 gene mutations and BRCA2 gene mutations carry an increased risk of prostate cancer. It's important to note that both of these mutation types may be associated with different cancers in different family members. So, for example, your healthcare provider may be more concerned that you have one of these mutations if you have young female relatives who have had breast cancer and another family member who has had pancreatic cancer than if you have a few male relatives who had prostate cancer at a later age.
  • Lynch syndrome (hereditary non-polyposis colorectal cancer or HNPCC): This syndrome is caused by mutations in DNA mismatch repair genes and is associated more strongly with colorectal cancer.
  • RNASEL mutations: These mutations affect a tumor suppressor gene.
  • HOXB13 mutations: These mutations are uncommon and are associated with prostate cancer in younger men.

Gene mutations can be confusing. It is not usually the gene mutation itself that gives rise to cancer. Many of the genes associated with an increased risk of cancer are tumor suppressor genes.

Tumor suppressor genes, such as the BRCA genes, code for proteins that work to repair damaged DNA or eliminate damaged cells from the body. When these proteins are abnormal, they are unable to do their job properly. Instead of being rightfully eliminated, a cell may progress to becoming a cancer cell.

People have two copies of each of the tumor suppressor genes, one inherited from each parent. Since both copies usually need to be mutated for cancer to develop, not everyone who inherits these mutations will develop cancer. Instead, they have a "genetic predisposition" to cancer. There is another type of gene, oncogenes, in which only one copy must be mutated, but this is much less common with regard to prostate cancer.

Whether or not you have a family history of prostate cancer, it's helpful to learn about hereditary cancer when looking at your risk of any type of cancer.

Frequently Asked Questions

  • Can having sex often affect your risk of prostate cancer?

    Possibly. Researchers have found that there may be a link between having frequent ejaculations and a lower-than-average risk of prostate cancer. In one study, men who ejaculated more than 21 times per month over their lifetime had one-fourth the risk of prostate cancer compared to men who reported four to seven ejaculations per month.

  • What’s the main reason men get prostate cancer?

    Researchers believe that a combination of factors are usually involved with the development of prostate cancer. In 10% of diagnoses, men have inherited a genetic disposition to the disease. Other things then increase their risk, including:

    • Age: 65 years of age or older
    • Ethnicity: Black men are at the greatest risk
    • Lifestyle: Diet, physical activity, and smoking
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15 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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