There’s one thing doctors want women to know after a study linked an increased risk of breast cancer to women who use hair dye or straighteners: Association does not equal causation.
That’s a formal way of saying that you can’t take two events and say one thing causes the other just because it appears there could be a connection.
Breast cancer is like a 1,000-piece puzzle. Known risk factors like obesity, family history and hormone status are just small pieces to the puzzle. There isn't just one specific piece of the puzzle that causes breast cancer.
While using hair dye or chemical straighteners may increase the risk of breast cancer, it’s important to clarify that using these products does not mean you’ll get breast cancer. This is just another piece of the large puzzle.
A deeper look into the study
The study was conducted using data from an ongoing study called the Sister Study — a review conducted by the National Institute of Environmental Health Sciences where participants are women with a sister who had breast cancer.
Researchers also looked at the participants over an eight-year period, where the number of breast cancer cases were tracked as the women aged. Age is also a risk factor for breast cancer, and the frequency of using hair dye is more likely as people age.
The risk discussed in the study was significantly higher among Black women — six times higher than white women. While the study did find that risk for breast cancer in Black women was significantly higher compared to white women, there is a proportion difference. Out of the 46,709 participants, 84% of the women were white. By using such a small population of Black women, the research makes the percentage appear bigger.
Proven risk factors of breast cancer with longstanding evidence include family history, age, exercise, diet, alcohol consumption, tobacco use and body mass index (BMI).
Early detection is key
Novant Health, along with the American Society for Breast Surgeons and the American College of Radiology, recommends women start getting their annual mammograms at 40.
For those who have a family history of breast cancer, doctors recommend beginning mammograms 10 years younger than the earliest onset of breast cancer in the family. For example, if a woman has a family member who got breast cancer at 45 years old, it would be recommended to start annual mammograms at age 35.
In addition to annual mammograms, breast self-awareness (formerly known as breast self-exams) is a good step toward early detection. Breast issues or concerns like a lump, swelling, irritation, redness or discharge should be communicated with your doctor immediately.