Hair Dye-Cancer Link Unproven, Say Researchers
Experts, Hair Dye Industry to Meet to Discuss Future Studies
Studies on Hair Dyes Ongoing continued...
Early this year, Yale researcher Tongzhang Zheng, ScD, reported that long-term use of dark shades of permanent hair dye can double the risk of non-Hodgkin's lymphoma. Zheng tells WebMD that his findings suggest but do not prove that hair dyes actually cause cancer.
A big unanswered question, he says, is whether the hair dye formulations used today pose the same risk as formulations used several decades ago.
"Hair dye companies have done a lot over the past 25 years to change these products to address concerns about safety," he says.
Johns Hopkins professor of epidemiology Kathy Helzlsouer, MD, who has reviewed the clinical studies on hair dye use and cancer, says the best clinical evidence suggests no increase in breast cancer and only a small increase in blood cancers in hair dye users. The bladder cancer risk associated with hair dye use is not clear, she says.
One problem with assessing hair dye risk is that bladder cancer is relatively rare among women and women are the primary users of hair dyes. Just 15,000 women in the U.S. are diagnosed with the disease each year, compared with 38,000 men.
Helzlsouer says several studies that are under way may clear up the confusion about the role of hair dyes in cancer.
"Hopefully this question will be settled soon, and we can tell women what the risks are, if any," she says.