Risk of Breast Cancer Links to Frequent Use of Hair Dye, Study Shows

December 8, 2019

by Andreea Sterea

New study revealed a link between the use of hair dye and straightener and higher risk of breast cancer in women already in risk. Before anyone panics, here are some things you need to know.

Hair Dye and the Risk of Breast Cancer

Scientists have scrutinized the possibility of chemicals in hair products to correlate with cancer in the past. However, as it goes with the study of potential health risks and correlational effects, research has not delivered clear results yet. Hair products have been studied as potential endocrine disruptors and carcinogens before. Yet, we are still looking for answers.

The new study was conducted by researchers from the National Institute of Environmental Health Sciences. Published in the International Journal of Cancer, it shows that women already in risk of cancer show higher risk of the disease upon frequent use of hair dye.

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The Sister Study

One of the limitations of correlation studies and health risks is usually the size of the sample. Also, inter-group diversity (or the lack thereof) and hidden variables produce unclear and often confusing results.

The NIEHS’ Sister Study offered scientists the opportunity to revisit older questions regarding any correlations between the use of hair dye and an increased risk of breast cancer. The scientists used a sample of 47,000 women. They all had sisters already diagnosed with breast cancer. This means the participants showed an already existing high risk of the disease.

The results revealed a link between high-frequency use of hair dyes and a significant incidence increase. As we said, such connections are not news in the medical field. Nevertheless, the Sister Study made progress with the sampling. 

  • The sample group included participants who identified as white, African American, or Hispanic.
  • This allowed the researchers to further break down the subject pool in narrower samples.
  • As a result, they could refine their findings for a better understanding on the link between the frequent use of hair dye, the risk of breast cancer, and ethnicity.

The Results on the Risk of Breast Cancer

This is what the researchers from the University of North Carolina found:

  • 60% increased risk of breast cancer in African-American women who use permanent hair dye every 5 to 8 weeks or more;
  • 8% increase in the risk of breast cancer for white women who use permanent hair dye with the same frequency as above;
  • 30% increase in the risk of breast cancer for women – regardless they are white, African-American, or Hispanic – who use hair straightening products once every couple of months. However, the results did not show a clear distinction between the racial groups.

Let’s remember two things here:

Scary headlines aside, the Sister Study brings if not clear, actionable results, at least a pathway to further research.

According to the chief of the NIEHS Epidemiology Branch, Dale Sandler,

“We are exposed to many things that could potentially contribute to breast cancer, and it is unlikely that any single factor explains a woman’s risk. While it is too early to make a firm recommendation, avoiding these chemicals might be one more thing women can do to reduce their risk of breast cancer.

Still A Lot of Research Ahead

Before you go throwing away your hair dye and other hair products, remember that we can infer correlations between a lot of chemicals and the risk of breast cancer. From cosmetics to plastics, and from toys to pesticides, we should rationally scrutinize their potential health risks. However, we are still far away from finding irrefutable proof of causal links. If you have concerns about breast cancer, or any type of cancer, first talk to your doctor. Then make the recommended lifestyle changes and improvements. Prevention is always the best treatment.

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