# Earlier menstruation in African American girls--why?

**URL:** <https://boards.straightdope.com/t/earlier-menstruation-in-african-american-girls-why/420848>\
**Category:** Factual Questions\
**Created:** [September 28, 2007, 6:49pm UTC](https://boards.straightdope.com/t/earlier-menstruation-in-african-american-girls-why/420848 "2007-09-28T18:49:36Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![Freudian\_Slit](https://avatars.discourse-cdn.com/v4/letter/f/5daacb/32.png) [@Freudian\_Slit](https://boards.straightdope.com/u/Freudian_Slit)\
**Post date:** [September 28, 2007, 6:49pm UTC](https://boards.straightdope.com/t/earlier-menstruation-in-african-american-girls-why/420848/1 "2007-09-28T18:49:36Z")

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From what I’ve read, menstruation is getting earlier in everyone, but especially earlier in African American girls. I’ve done searches here on the boards, but I didn’t find anything about AA girls specifically.

Is there any reason why this would happen? Reaching a certain body weight is often considered a “trigger” for menstruation, or so I’ve read. Would this have anything to do with them having a higher percentage of body fat?

Thanks, all.

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**Author:** ![Freudian\_Slit](https://avatars.discourse-cdn.com/v4/letter/f/5daacb/32.png) [@Freudian\_Slit](https://boards.straightdope.com/u/Freudian_Slit)\
**Post date:** [September 30, 2007, 9:40pm UTC](https://boards.straightdope.com/t/earlier-menstruation-in-african-american-girls-why/420848/2 "2007-09-30T21:40:04Z")

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Just wanted to bump this as it’s been a few days, and I’m still curious.

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**Author:** ![threemae](https://avatars.discourse-cdn.com/v4/letter/t/5f9b8f/32.png) [@threemae](https://boards.straightdope.com/u/threemae)\
**Post date:** [September 30, 2007, 10:38pm UTC](https://boards.straightdope.com/t/earlier-menstruation-in-african-american-girls-why/420848/3 "2007-09-30T22:38:20Z")

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Well, the answer is that no-one really knows. Here’s an article from _Pediatrics_ that ought to be available to everyone.

[http://pediatrics.aappublications.org/cgi/reprint/111/4/844](http://pediatrics.aappublications.org/cgi/reprint/111/4/844)

The Conclusions section is relatively brief, but it’s major points are that:  
There’s definitely a tendency for black girls to reach menarche (first period) about three months prior to white girls and this effect exists even after “factoring out” differences in BMI (body weight). Most of the apparent change in the average age of menarche in the American population is probably due to changes in BMI and demographic trends. For example, hispanics also tend to have an earlier age of menarche.

[http://www.ncbi.nlm.nih.gov/sites/entrez?cmd=Retrieve&db=PubMed&list\_uids=16356426&dopt=Citation](http://www.ncbi.nlm.nih.gov/sites/entrez?cmd=Retrieve&db=PubMed&list_uids=16356426&dopt=Citation)

So, BMI might be the main cause for the difference in average age of menarche, but there are apparently other reasons as well.

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**Author:** ![Omega\_Glory](https://avatars.discourse-cdn.com/v4/letter/o/7c8e57/32.png) [@Omega\_Glory](https://boards.straightdope.com/u/Omega_Glory)\
**Post date:** [September 30, 2007, 11:51pm UTC](https://boards.straightdope.com/t/earlier-menstruation-in-african-american-girls-why/420848/4 "2007-09-30T23:51:49Z")

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There was some question about whether hormones in hair care products could be the cause of this, but nothing has been proven.

[http://www.ncbi.nlm.nih.gov/sites/entrez?db=pubmed&cmd=Retrieve&dopt=AbstractPlus&list\_uids=17127015&itool=pubmed\_DocSum](http://www.ncbi.nlm.nih.gov/sites/entrez?db=pubmed&cmd=Retrieve&dopt=AbstractPlus&list_uids=17127015&itool=pubmed_DocSum)

Here’s some information, although it’s about estrogens in products increasing the risk of breast cancer in black women.