Duration and intensity of tobacco smoking and the risk of papillary and non-papillary transitional cell carcinoma of the bladder

To evaluate the impact of tobacco smoking on specific histological subtypes of transitional cell carcinoma of the bladder (TCC). Between 2003 and 2009, we conducted a hospital-based case-control study in Italy, enrolling 531 incident TCC cases and 524 cancer-free matched patients. Odds ratios (OR) and corresponding 95% confidence intervals (CI) were estimated through multiple logistic regression models. Compared to never smokers, TCC risk was threefold higher in former smokers (95% CI 2.07-4.18) and more than sixfold higher in current smokers (95% CI 4.54-9.85). TCC risk steadily increased with increasing intensity (OR for a parts per thousand yen25 cigarettes/day 8.75; 95% CI 3.40-22.55) and duration of smoking (OR for a parts per thousand yen50 years 5.46; 95% CI 2.60-11.49). No heterogeneity emerged between papillary and non-papillary TCCs for smoking intensity and duration, but the risk for those who had smoked for a parts per thousand yen50 years was twice for non-papillary TCC (OR 10.88) compared with papillary one (OR 4.76). Among current smokers, the risk for a 10-year increase in duration grew across strata of intensity (p-trend = 0.046). Conversely, the risk for a 5-cigarette/day increase in smoking intensity was quite steady across strata of duration (p-trend = 0.18). Study results suggested that duration of smoking outweighs intensity in determining TCC risk, with limited differences across histological subtypes. Elimination of tobacco smoking may prevent about 65 % of TCCs.