Fibroids are very common in black women with an estimated 55% of black women expected to develop them. This is significantly more common than in white women with black women being 2-3 times more likely to develop fibroids than their white counterparts.

The reason that fibroids are more common in black women is not fully understood but it is thought to be a combination of genetic and lifestyle factors.

The quest to understand why fibroids are more common in black women is an ongoing one, and one area that was explored a couple of years ago by researchers at Boston University was whether relaxers (chemical hair straighteners) increase a women’s risk of developing fibroids.

Relaxers are seemingly a good place to start when it comes to identifying factors that put black women at a higher risk of developing fibroids. This is a product that is specifically used by black women and is used by millions of us worldwide.  But, more importantly, as fibroids can be stimulated by the hormones oestrogen and progesterone and relaxers are known to contain chemicals that behave like hormones (phthalates), then logically we can hypothesise that use of relaxers may have an impact of the development of fibroids.

As part of the Black Women’s Health Study in the US, researchers explored whether relaxers may play a part in the development of fibroids. This study included 23,580 black women from across the US and they found a very slight increase (17% increase) in the rate of fibroids when women who  used relaxers were compared with women who had never used relaxers. They also found that there was a slightly positive trend when they looked at how often people used relaxers, how long and how many relaxer burns they experienced. So for example women who had used relaxers for more than seven years had the highest rate of fibroids, but this was still only slightly higher (23% higher) than women who never used relaxers.

Looking at this we could say that the findings suggest that relaxers may play a part in the development of fibroids but when you delve deeper it is harder to say for sure. Firstly, the study shows an association between fibroids and relaxers it doesn’t actually confirm that relaxers cause fibroids. Also, researchers found through DNA testing that black women with more African ancestry used relaxers more than those with more European ancestry and once they took ancestry into account there was less of a link between fibroids and relaxers. What this means is that the association between relaxers and fibroids in this study may have had nothing to do with the relaxers  playing a part in the development of fibroids but it was actually the degree of African ancestry that is the important factor.

The researchers therefore stated that:

“ We cannot rule out the possibility that greater African ancestry, thought to increase genetic predisposition to uterine leiomyomata  (fibroids), explains part or all of the observed association”.

Additionally, researchers didn’t have any information on the brands of relaxers women used or the exact chemicals that women would have been exposed to and how much they were exposed to. This makes it hard to say if women were in fact exposed to the hormone-like chemicals that are of concern when it comes to fibroids.

The take home message is that relaxers probably do not play a major role in the development of fibroids and if they do their impact is very small.  It would appear that the main risk factor is African Ancestry.

We do know that there are some lifestyle factors that can reduce a women’s risk of fibroids. These include exercise, maintaining a healthy weight, reducing your red meat consumption and eating a diet high in green vegetables.  So, we can all reduce our risk by adopting a healthy lifestyle

You can read the original research paper from the Black Women’s Health Study below.