The cause of bladder cancer remains unknown, although certain risk factors for the disease have been identified. Smoking is the most important risk factor, with smokers at least three times more likely to develop bladder cancer than non-smokers. Bladder cancer risk factors include:

Bladder defects from birth
Chemotherapy and radiation therapy
Chronic bladder infections and irritations
Exposure to certain chemicals including aromatic amines
Low fluid consumption
Personal or family history of bladder cancer
Being male and/or white 
Some medications and dietary supplements 
Exposure to arsenic in drinking water

Exposure to these risk factors does not guarantee that bladder cancer will develop. Likewise, bladder cancer can still develop in the absence of all of these risk factors. They have merely been found to increase the chances of the disease occurring. People who work in the following industries or who have the following professions also have an increased risk of bladder cancer, likely due to exposure to certain chemicals:

-- Hairdressers
-- Truck drivers.
-- Printing
-- Painters
-- Machinists
-- Manufacturing of rubber, leather, textiles and paint products