White and African American women who regularly dye their hair dark brown or black, or chemically straighten their hair, have a higher risk of breast cancer, new research has found.
The worrying findings come out of a study, published in the journal Carcinogenesis, of more than 4,000 women. It found a significant increase in breast cancer risk among black women who used dark shades of hair dye and white women who used chemical relaxers.
Women from New York and New Jersey aged between 20 and 75 were asked about their hair product habits. Nearly 2,280 of them were breast cancer survivors.
Breaking down the study's findings, white women who used chemical relaxers had a 74 percent increased risk of breast cancer, compared to those who did not, and black women who reported using dark hair dye had a 51 percent increased risk.
For white women who did both- used dark hair dye regularly and chemically straightened their hair, the breast cancer risk was even greater.
Interestingly, 88 percent of black women had used chemicals to relax their hair, with only five percent of white women using them. While 58 percent of white women used dark hair dye, as opposed to only 30 percent of black women.
The results showed a marked increase risk in the minorities - white women who used chemical straighteners and black women who dyed their hair dark.
But the lead author of the study said while there was a possible link between dark hair dye, chemical straighteners and cancer, it didn't prove a connection.
Lead author Adana Llanos, an epidemiologist at the Rutgers School of Public Health in Piscataway, New Jersey, told The Chicago Tribune: "Our findings do not suggest that simply using hair dyes, relaxers or both will cause a woman to get breast cancer.
"The reality is that we regularly encounter a variety of harmful exposures, which we have no control over.''
But she cautioned women to be more aware of the products we use on our bodies.
"A lot of people have asked me if I'm telling women not to dye their hair or not to use relaxers," she told Reuters. "I'm not saying that. What I think is really important is we need to be more aware of the types of exposures in the products we use."
Llanos said it's not yet understood why the chemicals in hair products may raise the risk of cancer, though she did implicate DNA damage, and the body's absorption of harmful chemicals as possible reasons.
It's also not understood why dark hair dyes in particular appear to be dangerous.
Epidemiologist, Professor Tamarra James-Todd, at the Harvard T.H. Chan School of Public Health in Boston, told Reuters that just because something is on the market, doesn't make it safe.
"We should really think about using things in moderation and really try to think about being more natural.
"Just because something is on the market does not necessarily mean it's safe for us," she said, qualifying that she was not involved in the study.
The study notes that further research into the area is needed.
"These novel findings provide support a relationship between the use of some hair products and breast cancer. Further examinations of hair products as important exposures contributing to breast cancer carcinogenesis are necessary.''
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