Bladder cancer risk in painters: a review of the epidemiological evidence, 1989-2004

Epidemiological studies on the potential association between painting and the risk of bladder cancer published after the Monograph of the International Agency for Research on Cancer N. 47 of 1989 have been systematically reviewed. These included four cohort studies on the incidence of bladder cancer among painters, with a pooled relative risk (RR) of 1.10 (95% confidence interval, CI, 1.03-1.18), based on 893 cases observed. The corresponding summary RR from four cohort studies on mortality was 1.23 (95% CI 1.11-1.37), based on 370 deaths. The pooled RR from 14 case-control studies and a pooled-analysis of other 11 case-control studies was 1.35 (95% CI 1.19-1.53), based on 465 cases exposed. Overall, the RR from all epidemiological studies was 1.17 (95% 1.11-1.27). Thus, recent epidemiological evidence indicates a moderate excess risk for bladder cancer in painters. Some studies, however, suggested that any such risk would have been greater for exposures in the distant past. Open issues for interpretation include residual confounding by social class and tobacco smoking, and understanding the time-risk relation. In particular, the potential residual risk related to exposure over the last two to three decades remains to be defined.