Case-control study of high risk occupations for bladder cancer in New Zealand

We conducted a nationwide case-control study of bladder cancer in adult New Zealanders to identify occupations that may contribute to the risk of bladder cancer in the New Zealand population. A total of 213 incident cases of bladder cancer (age 25-70 years) notified to the New Zealand Cancer Registry during 2003 and 2004, and 471 population controls, were interviewed face-to-face. The questionnaire collected demographic information and a full occupational history. The relative risks for bladder cancer associated with ever being employed in particular occupations and industries were calculated by unconditional logistic regression adjusting for age, sex, smoking and socio-economic status. Estimates were subsequently semi-Bayes adjusted to account for the large number of occupations and industries being considered. An elevated bladder cancer risk was observed for hairdressers (odds ratio (OR) 9.15 95% Confidence Interval (95%CI) 1.60-62.22), and sewing machinists (OR 3.07 95%CI 1.35-6.96). Significantly increased risks were not observed for several other occupations that have been reported in previous studies, including sales assistants (OR 1.03 95%CI 0.64-1.67), painters and paperhangers (OR 1.42 95%CI 0.56-3.60), sheet metal workers (OR 0.39, 95%CI 0.15-1.00), printing trades workers (OR 1.11 95%CI 0.41-3.05) and truck drivers (OR 1.36 95%CI 0.60-3.09), although the elevated odds ratios for painters, printers and truck drivers are consistent with excesses observed in other studies. Nonsignificantly increased risks were observed for tailors and dressmakers (OR 2.84 95%CI 0.62-13.05), rubber and plastics products machine operators (OR 2.82 95%CI 0.75-10.67), building workers (OR 2.15, 95%CI 0.68-6.73), and female market farmers and crop growers (OR 2.05 95%CI 0.72-5.83). In conclusion, this study has confirmed that hairdressers and sewing machinists are high risk occupations for bladder cancer in New Zealand, and has identified several other occupations and industries of high bladder cancer risk that merit further study.