Causes and Risk Factors of Bladder Cancer

While bladder cancer is not 100% preventable, you may be surprised to learn there are some things you can do to lower your risk of developing it, like quitting smoking. That being said, not all causes of bladder cancer are within your control, like a genetic predisposition for the disease.

However, risk factors—whether or not they are in your control—do not completely predict your likelihood that you will get bladder cancer. In other words, just because you smoke or just because you have a family history of bladder cancer does not mean you will definitively get it.

Ultimately, your risk of developing bladder cancer—like the vast majority of cancers—stems from a complex interaction between your genes and your environment. 

Common Causes

Let's explore certain factors that increase your chances of being diagnosed with bladder cancer and what you can do to minimize those chances.

Chemical Exposure at Work

Exposure to certain chemicals in a person's workplace, like aniline dyes and other types of aromatic amines, may increase the risk of developing bladder cancer. Researchers estimate that 5.3 percent of all bladder cancers, and 7.1 percent of bladder cancers in men, arise following occupational exposure.

Research suggests that the risk of developing bladder cancer holds for more than 30 years after the workplace exposure to these chemical carcinogens ends. Examples of occupations linked to a higher risk of bladder cancer include:

• Textile, rubber, leather, metal, dye, petroleum, or chemical workers
• People who work with printing materials
• Painters
• Hairdressers who work with dyes
• Dry cleaners
• Truck drivers (exposure to diesel fumes)
• Shoe polishers
• Drill press operator

Chronic Bladder Inflammation

Certain health conditions, like recurrent or chronic untreated urinary tract infections, bladder stones, bladder dysfunction from nerve problems, and those with an indwelling urinary catheter may develop chronic inflammation of the bladder.

This inflammation can increase the risk of getting bladder cancer, especially a specific type of bladder cancer called squamous cell carcinoma. This type, however, only accounts for about 1 to 2 percent of all bladder cancers.

Additionally, chronic and untreated infection with a parasite called Schistosoma haematobium—found in contaminated fresh water sources—is linked mostly to squamous cell carcinoma of the bladder.

Arsenic in Water

Arsenic found in drinking water has been associated with a higher risk of bladder cancer. Most sources of water that contain higher arsenic levels come from wells. 

Arsenic levels in drinking water are elevated in certain areas of the world, like parts of Taiwan, Japan, Bangladesh, and western South America. Some rural parts of the western United States also have natural arsenic in the water. But, be assured that for the majority of people in the United States, drinking water is not a major source of arsenic.

Medication and Treatment

Certain drugs and therapies have also been linked to bladder cancer, including:

• Long term use of diabetes medications in a class known as thiazolidinediones (scientific data is still mixed)
• A history of taking the chemotherapy medication Cytoxan (cyclophosphamide)
• A history of radiation therapy for pelvic cancer (prostate, testicular, cervical, or ovarian cancer) 

Other Influences

• Age (90%of those with bladder cancer are over the age of 55, according to the American Cancer Society)
• A personal history of another cancer in the urinary tract system (kidney, ureter, or urethra)
• A personal history of bladder cancer (a new tumor can form in a different location within the bladder)

Genetic Factors

There are some factors that increase your risk of developing bladder cancer that simply cannot be changed. These include:

• Gender (Bladder cancer is more common in men than in women.)
• Race (Caucasians are twice as likely to develop bladder cancer as African-Americans.)
• Certain birth defects of the bladder
• Family history of bladder cancer 

A family history of bladder cancer may or may not be related to a person's genetic makeup. For instance, certain genetic syndromes or mutations—which occur when cells in your body are dividing—are linked to getting bladder cancer; whether you inherit this is out of your control.

Research suggests that a younger age for the onset of bladder cancer may be more likely to be inherited. However, this is not a hard and fast rule.

But, a family history may be more within your control if your loved one develops bladder cancer because of an exposure, like to cigarette smoke or a chemical.

Lifestyle Factors

There are some causes of bladder cancer that may be well within your control to address in your daily life.

Cigarette Smoking

Scientific research has consistently shown that cigarette smoking increases the chance that a person will develop bladder cancer.

In an analysis of more than 450,000 people, former cigarette smokers were two times more likely to develop bladder cancer than non-smokers. And, current smokers were four-fold more likely to develop bladder cancer. People who smoke pipes or cigars were also found to be at a higher risk of developing bladder cancer, although the risk was smaller than in those who smoke cigarettes.

While this study supports the important role cigarette smoking plays in getting bladder cancer, it also suggests that stopping smoking can significantly decrease your risk, although not eliminate it.

How much and how long a person smokes also matters. According to a study in Urology, people who were heavy smokers had a higher-grade tumor—meaning cancer cells looked very abnormal—at a more advanced stage—meaning cancer had spread farther—at the time of diagnosis, compared to those who never smoked or were light smokers. (Heavy smoking was defined as 30 or more pack years and light smoking was defined as less than 30 pack years.)

The precise mechanism that cigarette smoking plays in the development of bladder cancer development is still unclear. That said, there are over 60 carcinogens in tobacco that have been linked to bladder cancer.

Supplements

Taking the Chinese herb Aristolochia fangchi is linked to both an increased risk of bladder cancer as well as other cancers in the urinary tract system.

Water Intake

Experts believe that the increased fluids may help clear out carcinogens in the bladder.