Temporal aspects of bladder carcinogenesis

A case-control study on 461 males with bladder cancer and 566 hospitalized male controls (all under age 70 and residing in the province of Turin, northern Italy) has been re-analyzed in an attempt to elucidate the role of different temporal variables. Both duration and independently cessation seem to play an important role in the carcinogenic activity of tobacco, whereas occupational exposures to aromatic amines were related to the age at first exposure. Relative risks for current smokers who have smoked less than 20, 20-29, and 40 plus years were 2.8, 6.5, and 8.2, respectively; for ex-smokers such estimates were approximately halved. In the case of occupational exposures, relative risks were 6.7, 3.1, and 1.5 for first exposure ages of less than 25, 25-34, and 35 plus years, respectively.