Objective: Estimating the risk of bladder cancer from cigar and pipe smoking is complicated by a small number of non-cigarette smokers included in most relevant studies.
Methods: We undertook a pooled analysis of the data on men from six published case-control studies from Denmark, France, Germany, and Spain, to assess the association between pipe and cigar smoking and bladder cancer, and to compare it with the risk from cigarette smoking. Complete history of tobacco smoking was ascertained separately for cigarettes, cigars, and pipe. Odds ratios (ORs) were estimated after adjusting for age, study, and employment in high-risk occupations.
Results: The pooled data set comprised 2279 cases and 5268 controls, of whom 88 cases and 253 controls smoked only cigars or pipe. The OR for pure cigarette smoking was 3.5 (95% confidence interval [CI] 2.9-4.2), that for pure pipe smoking was 1.9 (95% CI 1.2-3.1) and that for pure cigar smoking was 2.3 (95% CI 1.6-3.5). The increase in the OR of bladder cancer that was observed with duration of smoking was non-significantly lower for cigars than for cigarettes.
Conclusion: Our results suggest that smoking of cigars and pipe is carcinogenic to the urinary bladder, although the potency might be lower than for cigarettes.