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Hair dye, chemical straighteners may raise breast cancer risk
Permanent hair dyes and chemical hair straighteners are associated with an increased risk for breast cancer, particularly in black women, according to a study published in the International Journal of Cancer.
“These findings suggest that women should consider their use of hair products in light of the fact that the chemicals in hair dye and chemical straighteners may influence their risk of developing breast cancer,” Alexandra White, PhD, head of the environment and cancer epidemiology group at the National Institute of Environmental Health Sciences (NIEHS), told Healio Primary Care.
“However, the overall risk is not large and chemical hair products are just one of many factors that may influence a woman’s chances of getting breast cancer,” she continued.
White and colleagues evaluated data from women who participated in the Sister Study, which included women with no personal history of breast cancer who have a sister who was diagnosed with breast cancer.
During the mean follow up period of 8.3 years for 46,709 women included in the study, 2,794 breast cancer cases were reported.
Within the cohort, 55% of women reported using permanent hair dye at enrollment. Researchers found that any permanent hair dye use in the last year was associated with an increased breast cancer risk of 45% (HR = 1.45; 95% CI, 1.1-1.9) in black women and 7% in white women (HR = 1.07; 95% CI, 0.99-1.16).
The risk was even greater in those who regularly used permanent hair dye. Use of these dyes every 5 to 8 weeks was associated with a 60% (HR = 1.6; 95% CI, 1.11-2.3) increase in breast cancer risk among black women, and a 8% (HR = 1.08; 95% CI, 0.98-1.18) increase in risk among white women.
Any use of chemical straighteners in the last year was associated with an 18% increased breast cancer risk in all women (HR = 1.18; 95% CI, 0.99-1.41), with an even greater risk in women who used them every 5 to 8 weeks (HR = 1.31; 95% CI, 1.05-1.63) compared with those who did not use such products. Women who nonprofessionally applied straighteners to others had a 27% greater risk for developing breast cancer (HR = 1.27; 95% CI, 0.99-1.62).
While the risks associated with chemical straightener use were similar between black women and white women, the amount of chemical straightener use varied significantly by race — 74.1% of black women reported using chemical straighteners vs. 3% of white women.
Researchers found that although there was not an increased risk for breast cancer in women who personally used semi-permanent or temporary dyes, those who had nonprofessionally applied semi-permanent dye to others had a 28% greater risk for breast cancer (HR = 1.28; 95% CI, 1.05-1.56).
“Physicians could consider sharing this evidence with their patients to inform their decisions regarding hair product use,” White said.
She noted that additional research is needed before official recommendations can be made. – by Erin Michael
Reference:
Eberle CE, et al. Int J Cancer. 2019;doi:10.1002/ijc.32738.
Disclosures: The authors report no relevant financial disclosures.