Jan. 26, 2004 -- Long-term use of permanent hair dye -- in dark colors -- doubles a person's risk of certain blood cancers, new research shows.
Earlier studies have linked permanent hair dyes to bladder cancer as well as to the group of diseases known as non-Hodgkin's lymphoma. Non-Hodgkin's lymphoma rates are up all over the world. Nobody knows why, says Yale researcher Tongzhang Zheng, ScD.
Zheng suspected that hair dyes might play a role. Use of hair dye is increasing. And the products -- especially the permanent types in dark colors -- may expose users to dangerous chemicals. So Zheng led a research team that analyzed hair dye use in 601 women with non-Hodgkin's lymphoma and in 717 similar women without cancer.
The results: An increased risk of non-Hodgkin's lymphoma was observed for women who reported the use of hair coloring products before 1980. Women who used dark-colored permanent hair-coloring products for more than 25 years doubled their risk of non-Hodgkin's lymphoma. The risk was nearly the same for women who used more than 200 applications of these products. No increased risk was seen in women who used semi-permanent dyes or temporary rinses.
So should women stop using permanent hair dyes?
"Hair coloring is a personal decision for all kinds of reasons," Zheng tells WebMD. "But if I am the person, if semi-permanent or temporary dyes could serve my issue, I would do it. Because these contain much less of the ingredients linked to cancer."
Zheng's report appears in the Jan. 15 issue of the American Journal of Epidemiology.