Tobacco and bladder cancer in males: increased risk for inhalers and smokers of black tobacco.

Relationships between risk of bladder cancer and tobacco smoking were assessed from a hospital-based case-control study conducted in France from 1984 to 1987. Smoking history was analyzed for 954 male patients (477 cases and 477 controls). The odds ratio (OR) of bladder cancer was estimated at 3.95 for all smokers vs. non-smokers. The risk increased with duration of smoking and with average daily cigarette consumption, but there was a significant interaction between these 2 parameters, since the risk only increased with average daily consumption when the duration exceeded 20 years. Black tobacco consumption and inhaling were both found to double the risk when analyzed separately, but their respective effects appeared to interact, and an elevated risk for smokers of black tobacco was only observed among inhalers. Smokers of black and blond tobacco also differed in the way in which the risk evolved with time after cessation of smoking. The OR decreased faster after cessation of smoking among smokers of black tobacco than among smokers of blond tobacco, but the residual risk was higher 15 years after cessation among the former than among the latter.