Personal permanent hair dye use is not associated with bladder cancer risk: evidence from a case-control study.

Whether personal hair dye use is associated with an increased bladder cancer risk has been controversial and there are limited available data addressing this issue. We used a large case-control study of 712 incident bladder cancer cases and 712 age-, gender-, and ethnicity-matched controls to evaluate this association. After adjusting for confounding variables, the use of permanent hair dye was not associated with bladder cancer risk in all subjects [odds ratio (OR), 0.81; 95% confidence interval (95% CI), 0.50-1.30], in women (OR, 0.90; 95% CI, 0.41-1.96), or in men (OR, 0.68; 95% CI, 0.36-1.29). The lack of association was not modified by duration of use, frequency of use, lifetime use, age at first use, or color of use in subsequent stratified analyses. Our data do not support personal hair dye use as an important risk factor for bladder cancer.