Objective: To explore the relationship between smoking and bladder cancer in China.
Methods: A multicenter case-control study was conducted from September 2005 to June 2008. A total of 432 bladder cancer patients, matched with 392 control cases, received a questionnaire including the type of exposure (active vs. passive smoking), the age of beginning and/or quitting smoking, smoking amount and time and depth of smoke inhalation.
Results: Both active smoking and passive smoking increased the incidence of bladder cancer (P < 0.05). Bladder cancer risk increased 1.89 times in active smokers and 1.88 times in passive smokers compared to non-smokers (P < 0.05). Smoke amount and time were significantly correlated with bladder cancer risk (P < 0.05). But the age of beginning smoking did not affect the bladder cancer risk (P > 0.05). Inhaling smoke into mouth or throat was also a risk factor for bladder cancer (P < 0.05).
Conclusion: There is a strong association between smoking and bladder cancer. Active and passive smoking, smoke amount and time, and the depth of smoke inhalation are risk factors for bladder cancer. The best way of preventing bladder cancer is never smoking.