Welcome to brain Stuff production of iHeart Radio. Hey brain Stuff, Lauren Bogelbaum. Here, With all the unknowns that exist around breast cancer and most cancers for that matter, it's generally safe to say that the disease doesn't result from any single behavior, food, habit, or action. A complex combination of genetic and environmental factors contributes to the development of breast cancer in certain individuals, and scientists continue to seek out
answers around which factors could be controlled, monitored, or even eliminated. Now, a study from researchers at the National Institutes of Health or NIH suggests that permanent hair dye maybe one of those factors that increases the risk of breast cancer and
should receive further examination. The study, published online in December of twenty nineteen and the International Journal of Cancer, details how scientists at the National Institute of Environmental Health Sciences, part of the ni H, discovered that regular use of permanent hair dye was to an overall nine increase in breast cancer risk. The statistics were especially significant in African
American women. Those who used permanent dies every five to eight weeks or more frequently had a sixty higher risk of breast cancer compared with white women, who had an eight percent increased risk. Semi permanent and temporary dies didn't seem to have this effect. Neither was found to increase
risk of breast cancer. For the NIH study, researchers used data from forty six thousand, seven hundred and nine women who participated in the Sister Study, which included more than fifty thou women across the United States in Puerto Rico from two thousand three to two thousand nine. The participants of the Sister Study were all between the ages of thirty five and seventy four, and each had a sister
who had been diagnosed with breast cancer. The idea is that because sisters typically share the same environment, genes, and experiences, researchers may stand a better chance at pinpointing risk factors and developing effective can through prevention strategies. But permanent hair dye was only part of the equation. Researchers also found that chemical hair straighteners were associated with an increased risk
of breast cancer. The data showed that women who used hair straighteners every five to eight weeks or more frequently were about more likely to develop breast cancer. Straighteners were used much more frequently among the African American participants, but the association between the product and increased breast cancer risk was similar in both African American and white women. So does this mean permanent hair dye and chemical hair straighteners
should be strictly banned from regular use. Researchers aren't sure. Human bodies are complicated, and further investigation is necessary to replicate the results and hopefully explain what caused those results. In the meantime, keep in mind that cancers usually can't be explained by the involvement of any single factor. In other words, don't panic, but anyone concerned about their breast
cancer risk may want to reevaluate their cosmetic routines. Today's episode was written by Michelle Konstantinovski and produced by Tyler Clang. Brain Stuff is a production of I Heart Radio's How Stuff Works. For more in this and lots of other health related topics, visit our home planet, how stuff Works dot com. And for more podcasts for my heart Radio, visit the iHeart Radio app, Apple Podcasts, or wherever you listen to your favorite shows.