Study: Beauty and the breast: hair product use and breast cancer risk


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Women who use hair products who are concerned about their risk for breast cancer

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Checked Healthy people with average cancer risk

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Checked Women under 45

Checked Women over 45

Checked Special populations: African-American and White breast cancer survivors


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Past studies using mostly animal models showed a link between use of hair products (dyes, straighteners and relaxers) and increased risk of certain cancers. In this study, researchers looked at data on hair product use among African-American (AA) and White women to see if certain types of hair products increased breast cancer risk, and how that risk might differ between race and breast cancer hormone status. (9/27/2017)

Contents

At a glance In-depth
Findings     Limitations             
Questions for your doctor Resources and references     


STUDY AT A GLANCE

This study is about:

Examining the link between hair product use and breast cancer risk among African-American and White women.

Why is this study important?

In the United States, breast cancer is the second leading cause of cancer deaths among all women— African-American (AA) women are at higher risk of dying from breast cancer than White women. One factor that may impact a woman’s breast cancer risk is use of hair products. In this study, researchers wanted to see if there was a link between breast cancer risk and use of certain hair products, including hair dyes, relaxers/straighteners, and deep conditioning creams. The results show a possible significant link between use of some hair products and increased risk for breast cancer.

Study findings: 

Women who participated in this study were asked about their use of hair dyes and relaxers: what shade they used, how often they used it, and for how long. Among the 2,005 women without breast cancer and the 2,280 women with cancer, hair dye use was more common among White women than African-American women, while use of relaxers and deep conditioners was more common in African-American women than White women.   

Hair dye and breast cancer risk:

  • In African-American women, breast cancer risk was increased among those who reported use of dark hair dyes and salon application of dyes.
  • In White women, no association was found between hair dye use and breast cancer risk.

Relaxers and breast cancer risk:

  • In African-American women, regular use of hair relaxers was not associated with increased breast cancer risk.
  • In White women, use of relaxers was associated with increased breast cancer risk; however, this finding must be interpreted with caution given the small sample size of White women who used relaxers in this study.

Deep conditioners and breast cancer risk:

  • Among all women in this study (cases and controls and AA and White), no association was observed between the use of deep conditioners and breast cancer risk.

What does this mean for me?

While the results of this study suggest there might be a link between use of certain hair products and an increased risk of breast cancer, this is just one study; the authors admit that further studies looking at this link are needed to confirm these results. Thus, this study should not be considered as proof of an effect but rather a potential association to be explored. For women concerned about environmental exposure to carcinogens and an increased risk of breast cancer though, the data suggest that it may be reasonable to choose your hair products carefully and even, decrease or discontinue their use. However, there is not enough evidence to support the conclusion that use of certain hair products cause increased risk of breast cancer.

Questions To Ask Your Health Care Provider

  • I've been diagnosed with breast cancer, is it okay for me to use chemical-based hair care products on a regular basis?
  • What is my risk for breast cancer?
  • Are their specific products or chemicals that are linked to cancer that I should avoid?

IN-DEPTH REVIEW OF RESEARCH

Study background:

Exposure to carcinogens in hair products and increased breast cancer risk has been explored previously, mostly in animal models. This study looked at possible associations between breast cancer and hair product use in African American (AA) and White women. The study was conducted by Adana A.M. Llanos and colleagues from Rutgers University and published in June 2017 in the journal Carcinogenesis. The results seem to indicate an association between hair product use and increased breast cancer risk; that risk differed by race, and in some cases, subtype of breast cancer.  However, researchers cautioned that more studies are necessary in humans to confirm that certain hair products increase breast cancer risk.

Researchers examined data of 4,285 women taking part in the Women's Circle of Health Study (WCHS). In that study, women were asked questions on many factors that might affect breast cancer risk: history of personal and family health, exposure before birth, use of hormones, reproductive history, physical activity, alcohol use, smoking history, vitamin use, and hair product use.

Researchers of this study wanted to know:

Whether the use of hair products (dyes, relaxers, straighteners) increases breast cancer risk in AA and White women.

Population(s) looked at in the study:

This study looked at data collected from 2002 to 2014 from the WCHS case-control study conducted in New York City and 10 counties in New Jersey. Eligible participants were ages 20-75 and able to complete an interview in English. A total of 4,285 women were included in the present analysis:

  • 2,280 had a breast cancer diagnosis (cases) 
    • 1,508 of these were AA
    • 772 were White 

2,005 had no history of breast cancer (controls)

  • 1,290 of these were AA 
  • 715 were White  

Study findings: 

Hair dye and breast cancer risk:

  • For AA women
    • Those who reported use of dark shades of hair dye had a 51% increased risk of breast cancer.
  • For White women
    • No comparable increase was seen.

Relaxers and breast cancer risk:

  • For AA women, regular use of hair relaxers was not associated with increased breast cancer risk.
  • In White women, although relaxer use was very low, use alone or together with hair dyes was associated with a 74% increase in breast cancer risk.

The researchers also looked at hair product use and increased risk of estrogen receptor-positive (ER+) vs. estrogen receptor-negative (ER-) breast cancer, because of the marked increase in ER+ cancers in the United States, and to see whether certain hair products might mimic estrogen or trigger a change in the body that somehow increases production of estrogen.

Among the 2,280 women with breast cancer: 

  • In AA women, an increased risk of ER+ breast cancer was associated with use of:
    • darker shades of hair dye
    • hair dye more than twice per year
    • hair dye applied in a salon   
  • In White women, use of relaxers or straighteners, either alone or together with hair dyes increased risk of ER-negative disease although in this study, the number of White women who regularly used relaxers or straighteners was very small. 

Limitations:

This study had several limitations. Because it was a retrospective case-control study (it retroactively compared people who had breast cancer with those who did not) researchers could not establish cause and effect. Recall bias also limited the results—the WCHS study relied on each participant to accurately remember and report her use of hair care products over the course of her lifetime. Nor did the current study ask women what brands of products they used, so researchers weren't able to identify links between cancer and specific ingredients. Lastly, due to the small number of ER+ breast cancer cases, more studies are needed to confirm the link between hair product use and this type of breast cancer.

Conclusions:

These findings suggest that there may be a link between hair products and breast cancer risk. The authors state that additional studies are needed to further determine if there is a link between hair product use and increased breast cancer risk.

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Posted 9/27/17

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