Prostate cancer doesn’t have a single cause. It develops when cells in the prostate gland accumulate DNA damage that allows them to grow uncontrollably, and a combination of age, genetics, hormones, body composition, and environmental exposures determines which men are most likely to develop it. An estimated 313,780 new cases will be diagnosed in the United States in 2025 alone, making it the most common non-skin cancer in men.
Age Is the Strongest Risk Factor
Prostate cancer is rare before age 45. After that, risk climbs steeply with each decade. CDC data from 2022 shows that only 5% of prostate cancer cases were diagnosed in men aged 45 to 54, while 52% were diagnosed between ages 55 and 69, and 43% in men 70 or older. The incidence rate jumps from about 59 per 100,000 men in the 45-to-54 age group to roughly 427 per 100,000 between 55 and 69, and then to 619 per 100,000 for men 70 and older.
This pattern reflects the fact that prostate cells accumulate genetic errors over a lifetime. The longer cells divide, the more opportunities exist for mutations that disable the body’s normal growth controls. Age also brings decades of hormone exposure, which plays its own role.
How Hormones Drive Prostate Cell Growth
The prostate gland depends on male hormones to function, and those same hormones contribute to cancer development. Testosterone gets converted inside prostate cells into a more potent form called DHT by an enzyme called 5-alpha reductase. DHT binds to receptors inside the cell, travels to the nucleus, and switches on genes that tell the cell to grow and divide.
In healthy tissue, this process is tightly regulated. In prostate cancer, all three versions of the 5-alpha reductase enzyme are often overactive, flooding cells with growth signals. Mutations in the hormone receptor itself can also make cells hypersensitive to these signals or even allow them to keep growing when hormone levels drop. At the same time, the normal process of programmed cell death gets shut down, so damaged cells that should be eliminated instead survive and multiply.
Genetics and Family History
About 10% of men diagnosed with prostate cancer carry an inherited gene mutation that raised their risk. The rest of cases are considered sporadic, meaning no single inherited genetic change has been identified as the driver. That said, family history still matters for sporadic cases. Having a father or brother with prostate cancer roughly doubles your risk, likely because of shared combinations of common gene variants that individually have small effects but add up.
The best-known high-risk genes are BRCA1, BRCA2, and HOXB13. Men with mutations in these genes face a significantly elevated lifetime risk, and BRCA2 and HOXB13 mutations in particular are linked to more aggressive, life-threatening forms of the disease. These are the same BRCA genes associated with breast and ovarian cancer in women, which is why men with a strong family history of those cancers may also carry elevated prostate cancer risk.
Race and Ethnicity
The gap in prostate cancer rates across racial groups is one of the starkest disparities in cancer medicine. African American men are 76% more likely to be diagnosed with prostate cancer compared to white men and 120% more likely to die from it. In a large study tracking over a million person-years, the crude incidence rate was 785 per 100,000 for African American men versus 647 for white men, and the mortality rate was 141 versus 82 per 100,000.
Asian American men, by contrast, are about 55% less likely to be diagnosed than white men, with an incidence rate of 410 per 100,000. However, some studies have found that when Asian American men do develop prostate cancer, they may have similar or even slightly higher rates of fatal disease compared to white men.
These differences aren’t purely genetic. They reflect a tangled mix of biology, diet, screening access, and healthcare quality. African American men in the study had lower rates of PSA screening than white men, which can delay diagnosis until the cancer is more advanced. Still, even after adjusting for lifestyle and screening differences, African American men had a 31% higher incidence and 67% higher mortality, suggesting that biological factors also play a role.
Body Weight and Central Obesity
Carrying excess body fat, particularly around the midsection, is consistently linked to more dangerous forms of prostate cancer. The relationship is nuanced: obesity doesn’t clearly raise the risk of low-grade, slow-growing tumors, but strong evidence connects higher BMI and larger waist circumference to advanced, high-grade, and fatal prostate cancer.
Waist circumference appears to be an independent risk factor even after accounting for overall BMI, which points to belly fat specifically as the problem. Fat tissue is metabolically active. It produces hormones and inflammatory signals that can promote tumor growth, alter how the body processes insulin, and change the hormonal environment in ways that may fuel aggressive cancer cells. Notably, this association is strongest for body fat measured in mid-to-late life rather than in early adulthood, suggesting that cumulative exposure to these metabolic disruptions matters. Taller height is also independently associated with more aggressive prostate cancer, though the reasons are less well understood and may relate to growth factor levels during development.
Diet: Calcium, Dairy, and Lycopene
Two dietary patterns have the most consistent evidence linking them to prostate cancer risk. High calcium intake, especially from dairy sources, is associated with increased risk of advanced and metastatic disease. A 2015 meta-analysis found that high intakes of dairy products, milk, cheese, total dietary calcium, and dairy-derived calcium all correlated with higher prostate cancer risk. The World Cancer Research Fund concluded in 2007 that there was probable evidence for this link. Interestingly, supplemental calcium from non-dairy sources didn’t show the same association with overall risk, though calcium supplements were tied to a higher risk of fatal prostate cancer specifically.
On the protective side, lycopene, the compound that gives tomatoes their red color, is consistently associated with lower risk. Men with higher lycopene intake had about a 9% reduction in total prostate cancer risk and a 28% reduction in lethal prostate cancer risk in one large study. The association is even stronger in men with a family history of the disease. Both blood levels and dietary intake of lycopene show this inverse relationship, and populations that eat more tomato-based foods generally have lower prostate cancer rates. Cooked tomatoes, tomato sauce, and tomato paste deliver more bioavailable lycopene than raw tomatoes.
Chemical and Environmental Exposures
Agent Orange, the herbicide mixture sprayed during the Vietnam War, is one of the most well-documented environmental risk factors. It was contaminated with a dioxin compound classified as a carcinogen since the 1990s. A study of over a million veterans found that Agent Orange exposure was independently associated with increased prostate cancer risk, and among non-Hispanic white veterans, the risk of being diagnosed with metastatic prostate cancer was 13% higher in exposed men. The U.S. government now considers Vietnam-era veterans presumptively at high risk.
Other occupational and environmental chemicals have drawn attention as well. Firefighters, agricultural workers, and men exposed to certain industrial solvents face elevated rates in some studies, though the evidence varies in strength depending on the specific chemical. The common thread is that these exposures can damage DNA directly or disrupt the hormonal pathways that regulate prostate cell growth.
Inflammation and Infection
Chronic inflammation of the prostate, called prostatitis, has long been suspected as a contributing factor. Some epidemiological studies have found that men with a history of prostatitis symptoms face elevated prostate cancer risk, and pathologists frequently find areas of chronic inflammation in prostate tissue removed during cancer surgery. The biological logic is straightforward: sustained inflammation generates reactive molecules that can damage DNA, and the constant cycle of tissue injury and repair creates more opportunities for mutations.
However, the evidence is far from settled. A recent study using a genetic analysis method designed to test cause-and-effect relationships found no clear causal link between prostatitis and prostate cancer across multiple large datasets. The statistical results were consistently nonsignificant. It’s possible that the association seen in earlier studies reflects shared risk factors or detection bias, since men with prostate symptoms are more likely to get screened and therefore more likely to be diagnosed with cancer that might otherwise have gone undetected.