Black women may be at greater risk for breast cancer because of their use of hair dyes and straighteners, according to a new study in the International Journal of Cancer.
Alexandra White, one of the study’s authors and head of the Environment and Cancer Epidemiology Group at the National Institute of Environmental Health Sciences, cautioned that people should not overreact to the findings, which were obtained from a sample in which black women made up fewer than 10 percent of the subjects.
“The take-home message is that these risks are potentially important, but we know that a lot of different factors contribute to a woman’s risk of breast cancer,” White said, as quoted by The New York Times. “We want women to have this information and take it into account in their lifestyle decisions, but to keep in mind that the risks associated with these are small.”
The researchers analyzed data from 46,709 women enrolled in a prospective study who were asked if they used hair dyes and straighteners and then followed for an average of eight years. Black women who reported using permanent hair dye at least every five-to-eight weeks had a 60 percent higher risk of developing breast cancer than women who did not use such products. White women did not have an elevated risk of breast cancer when using permanent hair dyes.
In addition, women of all races who said they used hair straighteners showed a 30 percent higher risk of breast cancer. Such products are mostly used by women of African-American descent, the researchers said.
Hair dye is used by about one-third of American women over the age of 18, the researchers said, noting that such products contain as many as 5,000 chemicals that can alter cellular biology.
The reasons for differences found in cancer incidence between black and non-black subjects remains unclear, though the authors note that people of different races use hair care products differently, and products designed for use by black women contain different and potentially more damaging chemicals.