Susan S. Devesa, PhD, an epidemiologist with the National Cancer Institute, tells WebMD that Gago-Dominguez's study is interesting but that it needs to be put in context. First, she says, women have a low risk of bladder cancer. The American Cancer Society reports that while there are almost 40,000 new cases of bladder cancer each year, only 15,100 of those are in women, she says. So while the possibility of an increased risk should not be ignored, such a risk can "only represent a small number of cases."
"And I think we need to consider that the use of hair dye has been increasing since the beginning of the last century, but there has not been a concordant increase in bladder cancer," Devesa says.
Gago-Dominguez says that more studies are needed to confirm her findings. But she says that women who use permanent hair dye might want to think about switching to a semi-permanent dye.
- According to a study in Los Angeles County, 19% of cases of bladder cancer may be linked to the use of hair dyes.
- Women who dye their hair 12 times or more each year for a period of 15 years, hairdressers who work for more than 10 years, and smokers have the highest risk of getting bladder cancer.
- Although hair dyes may increase the risk of getting bladder cancer, such a risk would represent a relatively small number of cases, since women account for only about 15,000 of the 40,000 new cases of bladder cancer diagnosed each year.